128M02-0133-F1 7.25 B&S Engine no compression

[itsgalf]

Hello, I came by a 2014 Toro Recycler with a 7.25 B&S Engine (128M02-0133-F1) on it that wasn't working. The condition looked pretty good, figured it would be easy to get running. I cleaned the carburetor, replaced spark plug and air filter. Doesn't start still even with some carb cleaner sprayed through spark plug hole. I purchased a compression tester and when I go to pull it over, it only reads <30 psi.



I don't have experience nor do I have many tools, where should I start trying to fix this? Lap the valves?
Do I need a leak-down setup?

Thanks,
Marco

 

[Rivets]

Did you check to see if you have spark? To test remove plug, plug it back into the rubber boot. Hold the side of the plug against the head while someone pulls the starter rope, while you watch to see a spark. No spark would mean your coil is probably bad.

 

[Padroo]

It could have a blown head gasket or you mentioned valves but check the valve clearance before you pull the valves out.

It's best to check compression on a hot engine but in your case. Put some oil down the cylinder and recheck compression, it should come up a lot if the rings are shot.

 

[Rivets]

A 128M02 engine is an L-head engine and it would be highly unlikely that the clearances are bad in four years. With the compression release mechanism it is difficult to get good compression measurements. I work on these engines everyday, check the simple things first. If you do have spark, a few of the auto parts stores loan out tools, check with them for a leak down tester, but I doubt you will need it.

 

[itsgalf]

Yeah I checked the spark as well. Looks good to me. Even got bit by it - put my finger over the spark plug hole while my wife pulled the mower over to see if it see if blowing, except I was still holding the spark plug at the time.

I opened up the crankcase and found that the timing gear was off 1 tooth. But I'm thinking that shouldn't really be the issue - but maybe it is?
Also the exhaust muffler is missing one of the screws (it's only being hold on with 1 screw). So that's telling me someone's been in this engine before.

The old head gasket looks in decent shape. Maybe I'll just change it and see if that helps.

I'll try the 'oil in the cylinder' thing as well.

Some pics

 

[Rivets]

Can’t really tell if you have any internal problem by looking at the pics. Would like to have seen them before you cleaned them up. Can you move the piston all the way down and talk a few pics of the cylinder walls. This will give us an indication of what might be going on. I still don’t understand your low compression on a four year old engine.