I inherited a very old Clarke generator, model CPB1200, fitted with a B&S 3.5HP engine, model 130292, type 3204 01. I can't get it to start and tried a compression test and only got 30psi. I suspect the rings are rusted in the piston as it probably has not been run for about 20 years. The engine does not have a detachable barrel so I need to remove the crankshaft to get at the piston. I have removed the flywheel but don't know how to remove the rotor from its taper on the crankshaft. It looks easily damaged so I suppose the usual puller type tools are not suitable. Should I just leave it on, split the crankcase and use a puller on the crankshaft?
Clarke Generator
- Thread starter fidom
- Start date
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Is this a vertical crank or horizontal crank engine? Its possible to extract the piston upwards through the cylinder head - if you can release the big end bearing.
Sorry, I don't know how to remove the generator rotor but I'd leave it on anyway, if that's possible.
Don't expect too much compression from a side valve engine.....if you have the head off, make sure both valves can fully close - i.e there's no crap under the valve seats.
John
Sorry, I don't know how to remove the generator rotor but I'd leave it on anyway, if that's possible.
Don't expect too much compression from a side valve engine.....if you have the head off, make sure both valves can fully close - i.e there's no crap under the valve seats.
John
Ah, I didn't know they were a bolt up big end, that makes it a lot easier. If I can get the valves out I will grind them in while it's apart. I have valve spring compressors but they are for overhead valve engines. It is a horizontal crank.
have you done a wet compression test to give you a clue if its valves or rings?
litl
litl
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Tip some petrol into the inlet and exhaust ports.....you'll soon see any leak.
The valves are held in by either a tiny collet, a keyhole shaped valve spring cap or a steel peg - but either way the springs are easy enough to compress with a home made forked tool.
John
The valves are held in by either a tiny collet, a keyhole shaped valve spring cap or a steel peg - but either way the springs are easy enough to compress with a home made forked tool.
John
I did remove the rotor by pushing a length of rod down the hole for the fixing bolt and then tightening a short bolt screwed into the tapped hole at the end if the rotor shaft. I saw this on a Youtube video so it was not my idea. I did not get the crankshaft out as I could not see the dot mark for lining up the valve timing. The main bearing covers the mark and I don't have a long leg puller for removing said bearing. I did get the piston out and the rings looked perfect. I also lightly ground in the valves so now I just need to get a gasket set.
Do check that you have a valve clearance.....this is done by grinding the valve stem so it can be overdone.
Usually the main bearing remains in the alloy cover which makes the timing marks visible.
If the engine still doesn't want to play, it may have contact breaker points which are tarnished, or carb problems.
Let's know how you get on!
John
Usually the main bearing remains in the alloy cover which makes the timing marks visible.
If the engine still doesn't want to play, it may have contact breaker points which are tarnished, or carb problems.
Let's know how you get on!
John
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