Anyone know older Briggs and Stratton engines?

[anonymous-user]

My father has an old Mountfield mower with a B&S 92502 3Hp engine, which will only run for about 10 minutes from cold.

After this it develops a loud clanking noise and runs very badly, often refusing to restart.

Its had a new spark plug and points recently, and we've now removed the crank and taken a look at the conrod, and there is what seems to me to be a lot free play in the big end - holding the crank vertically I can rotate the conrod vertically by about 4mm at the crown of the piston.

Is this a normal amount of free play in a big end? The small end has no free play at all.

There also appears to be impact marks and material missing on one side of the bearing cap, along the edge where it runs next to the crank. The bearing surfaces are lightly scored but look OK to me. It has no removable bearings, just the rod and cap straight onto the crank.

Anyone know if this engine can be saved?

thanks
James

[spikeyhead]

I'm not normally into linking to other motoring forums, but where else are you likely to find a huge thread with lots of useful info on Briggs and Stratton engines.

http://www.honestjohn.co.uk/forum/post/index.htm?t...

happy reading.

[spikeyhead]

I'm not normally into linking to other motoring forums, but where else are you likely to find a huge thread with lots of useful info on Briggs and Stratton engines.

http://www.honestjohn.co.uk/forum/post/index.htm?t...

happy reading.

[anonymous-user]

thanks for the info.

In the end we completely dismantled the engine, right down to removing the crank, flattened the cylinder head on some wet and dry, cleaned it all up, put it back together and now it seems to run really nicely, with none of the problems of before. I think perhaps the head was not sealing properly before as the head bolts seemed quite loose to me and there was a lot of crud on the mating faces.

I don't know how long that loose rod will last but for the moment it's much better.

It's so much fun working on an engine when you don't need it to get you to work the next day

[tr7v8]

It'll be a roller bearing big end so will have a bit of play, not sure if that is too much though.
One tip I was given by a local garden repairer place that fixed one of my B & S engines was not to use multigrade oils, only a monograde 30 or 40 weight.

[Harpo]

4 mm of play? We're all doomed Captain Mainwaring!

[ruaricoles]

tr7v8 said:

One tip I was given by a local garden repairer place that fixed one of my B & S engines was not to use multigrade oils, only a monograde 30 or 40 weight.

Do you know why? We've recently bought a Hayter mower with a B&S engine (very happy with it), and the manual says either SAE30 or a couple of multigrades are fine (depending on temp range). I've stuck some suitable multigrade in it (had some already), but is there a reason I should buy SAE30 instead?

Thanks

Ruari

[tr7v8]

ruaricoles said:

tr7v8 said:

One tip I was given by a local garden repairer place that fixed one of my B & S engines was not to use multigrade oils, only a monograde 30 or 40 weight.

Do you know why? We've recently bought a Hayter mower with a B&S engine (very happy with it), and the manual says either SAE30 or a couple of multigrades are fine (depending on temp range). I've stuck some suitable multigrade in it (had some already), but is there a reason I should buy SAE30 instead?

Thanks

Ruari

Not sure why & this was a around early 90's but a well respected local repairer came out with it. Maybe it is because of the roller bearings big end & splash lubrication? My poor Westwood with an 11hp B & S was worked very hard though.