Getting an old outboard running smoothly
Discussion
Afternoon all, just rediscovered an old project..
I have a very (very very) old outboard motor in the shed that was bought a few years ago to act as a tender to my grandads canal boat on a couple of occasions, it stopped getting used probably 2-3 years ago and has since been stored in my shed, and started only a couple of times.
It was bought 2nd hand when it was already a relic, and has no identifying marks other than a '2' on the back in Mariner colours.
I started it for the first time in about a year today (amazingly enough started on the 2nd pull) and it is running very poorly (at least to my untrained ear):
- the throttle response is all over the place
- will only run for more than a minute with the choke fully open, and even then it will cut out after a couple of minutes more
- the throttle lever also appears to be sticking
- nearly vibrated a full bin of water over
- Will only start in either forward or reverse (Can't tell which, as theres no indicator and I don't have a boat to test it on - only a bin of water!)
- Will only start with near full throttle
I'm guessing some fresh fuel will help? As the current stuff has been in a jerry can for a couple of years.
Does anyone have any advice on how to get it running well again (and possibly quieten the fecker down)?
I have limited mechanical knowledge, but I would like to try and fix it myself, as it's not worth having it professionally repaired!
I have a very (very very) old outboard motor in the shed that was bought a few years ago to act as a tender to my grandads canal boat on a couple of occasions, it stopped getting used probably 2-3 years ago and has since been stored in my shed, and started only a couple of times.
It was bought 2nd hand when it was already a relic, and has no identifying marks other than a '2' on the back in Mariner colours.
I started it for the first time in about a year today (amazingly enough started on the 2nd pull) and it is running very poorly (at least to my untrained ear):
- the throttle response is all over the place
- will only run for more than a minute with the choke fully open, and even then it will cut out after a couple of minutes more
- the throttle lever also appears to be sticking
- nearly vibrated a full bin of water over
- Will only start in either forward or reverse (Can't tell which, as theres no indicator and I don't have a boat to test it on - only a bin of water!)
- Will only start with near full throttle
I'm guessing some fresh fuel will help? As the current stuff has been in a jerry can for a couple of years.
Does anyone have any advice on how to get it running well again (and possibly quieten the fecker down)?
I have limited mechanical knowledge, but I would like to try and fix it myself, as it's not worth having it professionally repaired!
The carb will probably need striping down and cleaning, its sounds like the idle jet is partly or fully blocked meaning it requires choke and throttle to run. If it was left with fuel in it it will have hardened, restricting any jets it was in at the time this will cause the mixture to be wrong (I'd say lean), causing the poor running.
syncro. said:
The carb will probably need striping down and cleaning, its sounds like the idle jet is partly or fully blocked meaning it requires choke and throttle to run. If it was left with fuel in it it will have hardened, restricting any jets it was in at the time this will cause the mixture to be wrong (I'd say lean), causing the poor running.
Thanks for the quick reply.It was left with fuel in it IIRC, I'll take it apart shortly - Does it require any specialist tools/knowledge to strip and clean a carb? Or is it just dismantle, remove gunk and re-assemble?
matty_doh said:
syncro. said:
The carb will probably need striping down and cleaning, its sounds like the idle jet is partly or fully blocked meaning it requires choke and throttle to run. If it was left with fuel in it it will have hardened, restricting any jets it was in at the time this will cause the mixture to be wrong (I'd say lean), causing the poor running.
Thanks for the quick reply.It was left with fuel in it IIRC, I'll take it apart shortly - Does it require any specialist tools/knowledge to strip and clean a carb? Or is it just dismantle, remove gunk and re-assemble?
Check the throttle/choke cable carefully as well; they sometimes fray at the nipple.
bitwrx said:
A pin/needle (of the sowing variety) is usually required.
Not for cleaning the jets I hope. Jet holes are drilled to precise sizes in brass, which is fairly soft, so it's easy to scratch or deform the inside of the hole with something too hard. A strand of copper wire is the hardest thing to use for cleaning jets; something softer is better, like a bristle off a brush.Always used to use trichloroethane for cleaning carbs, good stuff (if you can get it, the ninnies have made this difficult these days).
Pigeon said:
bitwrx said:
A pin/needle (of the sowing variety) is usually required.
Not for cleaning the jets I hope. Jet holes are drilled to precise sizes in brass, which is fairly soft, so it's easy to scratch or deform the inside of the hole with something too hard. A strand of copper wire is the hardest thing to use for cleaning jets; something softer is better, like a bristle off a brush.Always used to use trichloroethane for cleaning carbs, good stuff (if you can get it, the ninnies have made this difficult these days).
To be honest, I haven't done anything like this before so I'm just going to give it a go and see what happens, if I come across any trouble I know people who can help. Oddly looking forward to having a go.
The motor casing is scratched and faded and looks rather naff, would a rub down with a few different grades of sandpaper, primer and hammerite or similar be suitably durable for a motor? May also buy some Mariner stickers off fleabay, just to make it look a bit nicer.
Edited by matty_doh on Saturday 27th March 19:16
matty_doh said:
Pigeon said:
bitwrx said:
A pin/needle (of the sowing variety) is usually required.
Not for cleaning the jets I hope. Jet holes are drilled to precise sizes in brass, which is fairly soft, so it's easy to scratch or deform the inside of the hole with something too hard. A strand of copper wire is the hardest thing to use for cleaning jets; something softer is better, like a bristle off a brush.Always used to use trichloroethane for cleaning carbs, good stuff (if you can get it, the ninnies have made this difficult these days).
Camera brushes will be too soft, I was thinking more of bristles off a broom or something like that.
Assuming it is a two-stroke, when they get left for a while, the lighter fractions of fuel in the carb tend to evaporate off leaving the lubricating oil behind clogging it up. A good clean will probably help a lot.
The other thing to bear in mind is that older two-stroke outboards tend to need a higher concentration of lubricant mixed in with the petrol - modern engines are often 50:1, but if it is very old it might need 25:1 or higher.
As regards to silencing it, you probably won't have much luck - A lot of the noise of old outboards comes from extremely poor intake silencing, with the inlet being little more than a hole and may not even have a filter.
The other thing to bear in mind is that older two-stroke outboards tend to need a higher concentration of lubricant mixed in with the petrol - modern engines are often 50:1, but if it is very old it might need 25:1 or higher.
As regards to silencing it, you probably won't have much luck - A lot of the noise of old outboards comes from extremely poor intake silencing, with the inlet being little more than a hole and may not even have a filter.
From the sounds of it and reading your posts this is a Yamaha/Mariner 2B, if it has a re-coil starter. If you have to wrap the pull cord around the flywheel each time then it’s an earlier 2A model. Without a pic I can’t say for sure. If it is one of the above, depending on the condition you’re in luck. No you can't make it any quieter I’m afraid! Also going back to your forward/reverse dilemma the 2A/B engines are direct drive so pull and go (spin 180 for reverse). NEVER try to run two strokes on old fuel and by old I mean 2-3 months and it will give you problems on the small 2 strokes.
Before I bore you to tears on the ins and outs on possibly the wrong engine
!! Can you post a pic or send me one via a PM?? I’ll be happy to help with service tips and pointers! 
Dunk.
Before I bore you to tears on the ins and outs on possibly the wrong engine
!! Can you post a pic or send me one via a PM?? I’ll be happy to help with service tips and pointers! Dunk.
Lots of good stuff here
I like trico for these jobs but, the teeth of hens run over whilst pecking rocking horse poo from the side of the road will be easier to get hold of nowadays
Ordinary Carburettor Cleaner aerosols are usually excellent a dissolving hardened fuel residues and usually only cost two or three quids at a car spares shop
And a repeat, please dont use steel pins needles or spikes on the jets. Unless you want to use it for a cutaway opened up museum piece
copper wire from flat electrical twin and earth is often a good size (if you only use one strand for the job)
I like trico for these jobs but, the teeth of hens run over whilst pecking rocking horse poo from the side of the road will be easier to get hold of nowadays
Ordinary Carburettor Cleaner aerosols are usually excellent a dissolving hardened fuel residues and usually only cost two or three quids at a car spares shop
And a repeat, please dont use steel pins needles or spikes on the jets. Unless you want to use it for a cutaway opened up museum piece
copper wire from flat electrical twin and earth is often a good size (if you only use one strand for the job)
having spent all weekend fixing a rotovator and a neighbours lawn mower id recomend a new plug as well - someone had fitted a car plug to the rotovator and the spark was rubbish - it would cough and splutter but wouldnt run - a proper 'lawn mower' plug had a huge spark and it ran happily into life (a good 'spares or repairs' buy off ebay & a cheap fix!!)
the lawn mower had been stood a couple of years and the petrol is stale, that wont run but the ignitor is kaput - the plug is very poor though - i tested it on the rotovator - very weak spark again.
the lawn mower had been stood a couple of years and the petrol is stale, that wont run but the ignitor is kaput - the plug is very poor though - i tested it on the rotovator - very weak spark again.
Many thanks all, just left the fuel tank draining now - fuel coming out doesn't look too great! Will get some fresh stuff when I have the chance. Will also update with a few pics when I get a chance.
Will also order a fresh spark plug and possibly impeller/oil - plenty on ebay , I believe Dunk1982 is correct, a quick google of a Yamaha 2B looks very very similar and seems to be of a similar vintage.
Will also order a fresh spark plug and possibly impeller/oil - plenty on ebay , I believe Dunk1982 is correct, a quick google of a Yamaha 2B looks very very similar and seems to be of a similar vintage.
Yammy 2B it is then
Now it may say Mariner on the cowl or serial number plate (located on the top of the saddle bracket, the older plates were tin and riveted on so may have corroded off) but these were made buy Yamaha so for any spare parts go to a Yam dealer, for this model they wont cost allot, I think a impeller for instance last time I sold one was about 6 quid. Spark plug for a points/condenser model like yours is a NGK B7HS (99% sure..) if you look inside where the plug goes you might be lucky enough to still have the sticker telling you. Points gap again 99% on this is 12-14 thou, cleaning and setting the points on these is a must and with that done, clean carb, fresh fuel on a 50-1 mix (TCW 3 oil 20ml to every liter of petrol) new spark plug you can start these by hand, and I mean by just giving the flywheel a spin with your hand!
Carb: on these very simple to clean, two screws to remove the float bowl (get a clean baking tray from that food place in the house.... kitchen that’s it! or buy one or use something similar to strip the carb on) when you remove it from the engine be sure to check the o-ring is still in the back of the carb, sometimes it can stick to the engine side. Hold the carb upright and remove the screws, then over the tray or whatever your using still holding the bowl to the carb turn it upside down so the screws drop out, this way when you remove the float bowl everything stays inside! Check the float height, with the carb upside down the float should be sitting level with the carb if that makes sense!? If it looks raised or low then you won’t get the correct amount of fuel in the bowl. Remove the float and unscrew the float arm and carefully remove so you get to the needle valve, check the tip and the whole needle for any damage, the brass seat should be cleaned, use a cleaner which you already have by the sounds of it and some extremely fine wet & dry paper, tear off a bit and roll it up so it fits in the seat and just give it a little twist round so it removes any deposits left from old fuel and oil and brings the shine back, don’t go mad, quick check is once clean try the needle valve in there, if its sticking then clean a little more. There’s one main jet to remove, you’ll need a small but wide flat blade so it fills the slot well when you go to remove the jet, if it’s tight and the screw driver isn’t wide enough you can break the top off the jet. SAME GOES FOR ANY NUT BOLT SCREW ON OLD (OR NEW!) OUTBOARDS, IF IT’S TIGHT LEAVE IT!! FORCE IT WITHOUT GENTLE HEAT AND IT WILL SHEAR! TRUST ME!
As said above use a thin piece of electrical wire to clear the jet if need be. From where you have removed the jet you will see another needle, this is attached to the throttle assembly (without getting too technical, just trying to keep it simple) this will also need a gentle clean as if its dirty it will have a affect on the idle (this can adjusted but best left alone for now) to remove undo the brass nut on top of the carb where the throttle arm goes up and down into the carb, think it’s a 13mm, undo just a little so that the aluminum part it screws into can be undone and removed, the barrel part with the needle sticking out has a slot down one side and a cut out on the other, the slot is so upon assembly it goes back in correctly ( you’ll see a dowel type thing inside for it to line up with) the other side you’ll notice is where the idle screw goes in to make its adjustments. Gently clean the needle, if it looks ok leave it. Assembly of the carb is just the opposite, you may have to adjust/ reline the throttle arm a little when you put the cover back onto the front of the carb, just undo that 13mm nut a little adjust the arm and nip back up. Again, if any parts look damaged or worn all can still be bought from Yamaha and don’t cost the world. Hope I haven’t confused the situation here!! All this is from memory too so anyone please feel free to correct me!!
I’ve serviced, stripped and rebuilt more of these things than ive had hot dinners and pretty sure I could do it blind folded!!
Oh and with the impeller, pay extra and buy the water pump kit, comes with all the bits you’ll need especially if it is old and hasn’t been serviced for a while.
And back to the serial number plate, if its there, look in the top right hand corner, there will be a tiny faint letter stamped on it, this is the age code ( F is a ’89) the serial number I think starts 6L5 S then numbers. S just stands for short shaft.
Come back tomorrow for water pump strip and service!!
Now it may say Mariner on the cowl or serial number plate (located on the top of the saddle bracket, the older plates were tin and riveted on so may have corroded off) but these were made buy Yamaha so for any spare parts go to a Yam dealer, for this model they wont cost allot, I think a impeller for instance last time I sold one was about 6 quid. Spark plug for a points/condenser model like yours is a NGK B7HS (99% sure..) if you look inside where the plug goes you might be lucky enough to still have the sticker telling you. Points gap again 99% on this is 12-14 thou, cleaning and setting the points on these is a must and with that done, clean carb, fresh fuel on a 50-1 mix (TCW 3 oil 20ml to every liter of petrol) new spark plug you can start these by hand, and I mean by just giving the flywheel a spin with your hand!
Carb: on these very simple to clean, two screws to remove the float bowl (get a clean baking tray from that food place in the house.... kitchen that’s it! or buy one or use something similar to strip the carb on) when you remove it from the engine be sure to check the o-ring is still in the back of the carb, sometimes it can stick to the engine side. Hold the carb upright and remove the screws, then over the tray or whatever your using still holding the bowl to the carb turn it upside down so the screws drop out, this way when you remove the float bowl everything stays inside! Check the float height, with the carb upside down the float should be sitting level with the carb if that makes sense!? If it looks raised or low then you won’t get the correct amount of fuel in the bowl. Remove the float and unscrew the float arm and carefully remove so you get to the needle valve, check the tip and the whole needle for any damage, the brass seat should be cleaned, use a cleaner which you already have by the sounds of it and some extremely fine wet & dry paper, tear off a bit and roll it up so it fits in the seat and just give it a little twist round so it removes any deposits left from old fuel and oil and brings the shine back, don’t go mad, quick check is once clean try the needle valve in there, if its sticking then clean a little more. There’s one main jet to remove, you’ll need a small but wide flat blade so it fills the slot well when you go to remove the jet, if it’s tight and the screw driver isn’t wide enough you can break the top off the jet. SAME GOES FOR ANY NUT BOLT SCREW ON OLD (OR NEW!) OUTBOARDS, IF IT’S TIGHT LEAVE IT!! FORCE IT WITHOUT GENTLE HEAT AND IT WILL SHEAR! TRUST ME!
As said above use a thin piece of electrical wire to clear the jet if need be. From where you have removed the jet you will see another needle, this is attached to the throttle assembly (without getting too technical, just trying to keep it simple) this will also need a gentle clean as if its dirty it will have a affect on the idle (this can adjusted but best left alone for now) to remove undo the brass nut on top of the carb where the throttle arm goes up and down into the carb, think it’s a 13mm, undo just a little so that the aluminum part it screws into can be undone and removed, the barrel part with the needle sticking out has a slot down one side and a cut out on the other, the slot is so upon assembly it goes back in correctly ( you’ll see a dowel type thing inside for it to line up with) the other side you’ll notice is where the idle screw goes in to make its adjustments. Gently clean the needle, if it looks ok leave it. Assembly of the carb is just the opposite, you may have to adjust/ reline the throttle arm a little when you put the cover back onto the front of the carb, just undo that 13mm nut a little adjust the arm and nip back up. Again, if any parts look damaged or worn all can still be bought from Yamaha and don’t cost the world. Hope I haven’t confused the situation here!! All this is from memory too so anyone please feel free to correct me!!
I’ve serviced, stripped and rebuilt more of these things than ive had hot dinners and pretty sure I could do it blind folded!!
Oh and with the impeller, pay extra and buy the water pump kit, comes with all the bits you’ll need especially if it is old and hasn’t been serviced for a while.
And back to the serial number plate, if its there, look in the top right hand corner, there will be a tiny faint letter stamped on it, this is the age code ( F is a ’89) the serial number I think starts 6L5 S then numbers. S just stands for short shaft.
Come back tomorrow for water pump strip and service!!
Great post Dunk1982, very much appreciated..
Gave it a brief clean and discovered a "Mariner 2B" plate riveted on - who knew dirt could hide so much information!
Took some crappy pics in the messy garage (It was raining!)
As it was after a quick clean;
Both side panels removed;
ID Plate Revealed!;
What I'm hoping to convert back to 'As new'
At first I had hoped just to get it running ok-ish again, but now I'm going to try and 'restore' it as it has potential.
Purchases so far;
- Rattle can primer
- Gloss black paint (Bought from a Marine shop, hopefully up to the job)
- Fresh grease
- Fresh 2 stroke oil
- Engine degreaser
To get;
- New spark plug + impeller
- fresh fuel
Gave it a brief clean and discovered a "Mariner 2B" plate riveted on - who knew dirt could hide so much information!
Took some crappy pics in the messy garage (It was raining!)
As it was after a quick clean;
Both side panels removed;
ID Plate Revealed!;
What I'm hoping to convert back to 'As new'
At first I had hoped just to get it running ok-ish again, but now I'm going to try and 'restore' it as it has potential.
Purchases so far;
- Rattle can primer
- Gloss black paint (Bought from a Marine shop, hopefully up to the job)
- Fresh grease
- Fresh 2 stroke oil
- Engine degreaser
To get;
- New spark plug + impeller
- fresh fuel
Glad to help! Miss working on the engines so always good to help someone else willing to have a go!
That plate should still have a letter code on it for the age, you'll just have to look real close!! From the pics it’s not a very very early one, looks like it’s got the plastic prop as well. As we have established it’s a Mariner badged one that’s as far as the connection goes! These are all Yamaha so as I said before go to Yam for your spares, and honestly purchase the whole water pump kit! You will need more than the impeller. This is a points condenser engine too.
Before you buy anything though start working on the engine first then you will save time and money as you can make a list and get everything in one hit! When I was working in the shop people would come in all the time for spares, and then be back a hour later for something else, that I probably told them they would need!!
Right, water pump!! This could go either way so be warned!
If you lucky this will be childsplay, if not... well be patient!!
First off remove the prop, take the split pin out and slide the prop off if its tight don’t worry the shear pin on the shaft might be a little bent causing it to bind on the prop. Check the shear pin, should be a soft silver steel, not brass, brass is too soft for a direct drive unit imo. These engines did have little rubber holders on them for spare shear pins and split pins, usually under the front of the cowling (engine cover) if your lucky its still there! I would purchase a couple of spare shear pins as well to keep with the engine.
Drain the gear oil, undo the two screws on the side of the gear box and check the oil coming out, if golden or black and stinky that’s fine, but if its milky then you’ve got water in there or worst case water just pours out!! Not the end of the world, just need to replace the seals. (Comes in the water pump kit) Gear oil you can buy a tube of EP90 from any marine shop.
To remove the gear box just undo the two 6mm bolts using a 10mm spanner, but go easy!! If they feel too tight they could be seized, apply gentle heat to any bolt that’s seized and slowly work it back and forth to release the salt gripping the threads, you can try WD40 etc but for serious cases you need to apply some heat and take your time! Trust me you don’t want to be drilling out these bolts...!!
Once undone you should just be able to pull the gearbox down, might need a little wedge or a tap just watch out for the cav plate and check your clearance before shoving anything in to leaver it with! If for the life of you it won’t budge don’t panic! These 2B are tough buggers and there are ways of making them talk!! If it refuses to come down the drive shaft has seized into the bottom of the crank shaft. No problem, just means you have to strip the gear box in place and remove the power head.
Now can you see why I suggest attacking the engine first before going out to buy spares!
Let me know how you get on with the above first before I carry on, if the gear box comes away without a fight your laughing, but you still have to strip it to change the impeller.
good luck!
That plate should still have a letter code on it for the age, you'll just have to look real close!! From the pics it’s not a very very early one, looks like it’s got the plastic prop as well. As we have established it’s a Mariner badged one that’s as far as the connection goes! These are all Yamaha so as I said before go to Yam for your spares, and honestly purchase the whole water pump kit! You will need more than the impeller. This is a points condenser engine too.
Before you buy anything though start working on the engine first then you will save time and money as you can make a list and get everything in one hit! When I was working in the shop people would come in all the time for spares, and then be back a hour later for something else, that I probably told them they would need!!
Right, water pump!! This could go either way so be warned!
If you lucky this will be childsplay, if not... well be patient!!
First off remove the prop, take the split pin out and slide the prop off if its tight don’t worry the shear pin on the shaft might be a little bent causing it to bind on the prop. Check the shear pin, should be a soft silver steel, not brass, brass is too soft for a direct drive unit imo. These engines did have little rubber holders on them for spare shear pins and split pins, usually under the front of the cowling (engine cover) if your lucky its still there! I would purchase a couple of spare shear pins as well to keep with the engine.
Drain the gear oil, undo the two screws on the side of the gear box and check the oil coming out, if golden or black and stinky that’s fine, but if its milky then you’ve got water in there or worst case water just pours out!! Not the end of the world, just need to replace the seals. (Comes in the water pump kit) Gear oil you can buy a tube of EP90 from any marine shop.
To remove the gear box just undo the two 6mm bolts using a 10mm spanner, but go easy!! If they feel too tight they could be seized, apply gentle heat to any bolt that’s seized and slowly work it back and forth to release the salt gripping the threads, you can try WD40 etc but for serious cases you need to apply some heat and take your time! Trust me you don’t want to be drilling out these bolts...!!
Once undone you should just be able to pull the gearbox down, might need a little wedge or a tap just watch out for the cav plate and check your clearance before shoving anything in to leaver it with! If for the life of you it won’t budge don’t panic! These 2B are tough buggers and there are ways of making them talk!! If it refuses to come down the drive shaft has seized into the bottom of the crank shaft. No problem, just means you have to strip the gear box in place and remove the power head.
Now can you see why I suggest attacking the engine first before going out to buy spares!
Let me know how you get on with the above first before I carry on, if the gear box comes away without a fight your laughing, but you still have to strip it to change the impeller.
good luck!
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