Starting an outboard that has been stood for 18 years

Starting an outboard that has been stood for 18 years

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james12345

Original Poster:

591 posts

237 months

Wednesday 3rd August 2011
quotequote all
Hi - I've recently bought a 20 foot boat that has been out of the water for 25 years, and came with an outboard. The outboard was last serviced / repaired / sorted back in 1993, and hasn't been used since. I've taken the cover off, and to be perfectly honest, was amazed at the condition - no rust, all moving parts look like they were greased yesterday, etc.

Now I'm planning on running it up (in a water butt) but was wondering what should be the best way to approcah. I was going to change the oil, check / clean the plug, and really just then connect up and turn the key! Is there anything else I should be thinking about first?

If it helps, I do have the workshop / service manual for the outboard, but it doesn't cover this sort of stuff unfortunately! It's a 1974 Johnson 50Hp 4 stroke.

Hooli

32,278 posts

201 months

Wednesday 3rd August 2011
quotequote all
I'd drop a bit of oil down the plug hole to try & free any stuck rings. Is there a way to then turn it over by hand & make sure it's not seized up before running it?
You might well have to strip the carb down & clean it out as old petrol can gum up & block all the jets etc.

rhinochopig

17,932 posts

199 months

Wednesday 3rd August 2011
quotequote all
Drain the oil and fuel, fill with fresh.

Then I would turn it over slowly by hand with the plugs out first to ensure that everything is moving as it should and also oiled. You may have problems with the carb too given the length of time it's been stood. Try it first and see it how it runs and if it's running rough the carb may need a service.

thinfourth2

32,414 posts

205 months

Wednesday 3rd August 2011
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rhinochopig said:
Drain the oil .
What oil?

tr7v8

7,196 posts

229 months

Wednesday 3rd August 2011
quotequote all
thinfourth2 said:
rhinochopig said:
Drain the oil .
What oil?
The engine oil & the leg oil, it is a 4 stroke according to the OP. Edited to add I'd change the waterpump impeller as well.

Searider

979 posts

256 months

Wednesday 3rd August 2011
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Very unlikely to be a 4 stroke if 1974.

Most manufacturers only started with 4 stroke outboards in the 1990s

- apart from Honda.

Put a little oil down the bores before turning it over.

Fresh petrol/ oil mix of at least 50:1. Maybe even 40:1 at that age.

Quite likely that the carbs will be gummed up - may need to strip them if no fuel gets through.

maser_spyder

6,356 posts

183 months

Thursday 4th August 2011
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Anybody mention changing the impeller yet?

If it starts, and there's no water pumping through, cut out immediately before it overheats (and potentially seizes), would be a shame to waste a good motor for the sake of a cheap rubber wheel.

Hooli

32,278 posts

201 months

Thursday 4th August 2011
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maser_spyder said:
Anybody mention changing the impeller yet?
Tr7v8 did.

MattYorke

3,773 posts

254 months

Thursday 4th August 2011
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Lots of good points above - just need to bring them all together.
1. Almost certainly will be a 2 stroke
2. I'd run the first bit of fuel through it on a 25:1 premix just to get everything lubed up. I suspect the motor was designed for 50:1, could be 40:1 however - a bit of a google should confirm. More modern motors were 50:1, but IIRC I had a johnson 8 of that vintage once that was 40:1.
3. Before attempting to start it, or even turn it over, I'd squirt a load of premix down the carbs to give the crank bearing and seals a bit of lube
4. Also give it a squirt of premix down each of the plugs, and turn it over slowly by hand and check that it's smooth. The make of break thing for the engine is whether the crank and needle roller bearings are still serviceable. Most other things can be fixed OK, but that would probably right it off.
(You could squirt neat 2 stroke oil in, but chances are it'd end up over oiled and foul the plugs)
5. The impeller will defo need changing - it will almost certainly be knackered.
If you can't/don't want to until it's running, if you pull the gearbox off, you might be able to connect the water pipe to a hose. I wouldn't run it with no water at all at any point. You could change the gearcase oil at the same time while the gearbox is off if you want.
6. Thermostats might be stuck.
7. Do use a TCW3 certified outboard oil - it's a bit different to what you'd put in your scooter or lawnmower.
8. Carbs could need rebuilding - depends on how it was left. I'd see if it fires on a squirt of fuel down the carb throats, and then take it from there. Might be lucky, might not.
9. For squirting premix etc down the carb throats and spark plug holes, I'd recommend using a model aeroplane primer bottle - available from all good model shops.