7 year old Craftsman 21 hp riding mower hard to turnover & start, High compression stroke. Model 331877 2371 G5, YT3000

[PNWguy]

Like has been mentioned you probably have a bad compression release but just a thought. If you have a compression tester you might want to check compression before you condemn the compression release. You'd hate to go to all the work of replacing a camshaft that didn't need replacing. You should be able to do that just like you did when you got it started. Once you get it past the initial stoppage it will probably keep turning over so you can get a reading. Anything over 100 psi would probably be a good indicator of a failed compression release or improper valve setting but it you've checked that. If the compression release isn't working the compression will probably be well over 100 psi.

Maybe someone mentioned this and I missed it but with the spark plug out you should be able to turn the engine over by hand with the rocker cover off and see if the compression release is bumping the valve open on the compression stroke. Just one man's opinion.

That’s great advice, I have to go through my boxes to see if I still have my tester. I used to have a tester but haven’t used it in many years. If not, I can probably find a friend that has one. I agree, I really don’t want to tear the engine apart if I don’t need to. I also did check my valve gaps and did a slight adjustment, not sure if a thousandth would make much difference. I should be getting my new starter gear today in the mail to change out.

 

[PNWguy]

how much have you spent on it so far?

I bought the mower for $375, replaced the starter for $ 85 plus tax. Oil, plug and a gas filter. Bought another starter gear $15, Around $500 So far.
I am donating this mower to our Local Church in town, if I can get it working reliably. I called a local repair guy to see what they would charge and he’s has a same motor he went through that he’s willing to sell to me for $450, if I give him my motor In exchange. Or repair my motor for about the same price if the cam bad for $375-400.

 

[Craftsman Garage]

I know, I can’t figure that one out too. By the way, What do you recommend for a battery CA‘s?

prob 300+, just depends what your budget is because i know that this project is starting to cost a bit

 

[Craftsman Garage]

I bought the mower for $375, replaced the starter for $ 85 plus tax. Oil, plug and a gas filter. Bought another starter gear $15, Around $500 So far.
I am donating this mower to our Local Church in town, if I can get it working reliably. I called a local repair guy to see what they would charge and he’s has a same motor he went through that he’s willing to sell to me for $450, if I give him my motor In exchange. Or repair my motor for about the same price if the cam bad for $375-400.

hmmm, thats a big tradeoff

 

[Craftsman Garage]

its really not that hard to replace the cam, its just right there after you take the oil pan off...

 

[Tiger Small Engine]

I bought the mower for $375, replaced the starter for $ 85 plus tax. Oil, plug and a gas filter. Bought another starter gear $15, Around $500 So far.
I am donating this mower to our Local Church in town, if I can get it working reliably. I called a local repair guy to see what they would charge and he’s has a same motor he went through that he’s willing to sell to me for $450, if I give him my motor In exchange. Or repair my motor for about the same price if the cam bad for $375-400.

Yep, around $400 to replace cam with compression release and labor sounds fair. I am doing one next week when cam comes in.

 

[Cajun power]

couple of points.
1. bertsmobile has really good advice...he is particularly reliable with his experienced suggestions.
2. just because you have a new battery does not mean you have GOOD WIRING AND CONNECTIONS. test and inspect every single red and black cable (heavy) wire and connection...Pay attention to the starter solenoid (red) and the flywheel solenoid starter (also red), and also the black heavy wire going to chassis ground. It might be just be a loose or corroded connection or a bad ground. If you have a clamp meter, you can measure the current across the heavy red cable connected between the starter solenoid and the flywheel solenoid starter. If the amps are low, you know you have a wiring issue a bad connection somewhere or the flywheel solenoid starter is bad. This assumes the battery you installed it GOOD AND FULLY CHARGED - not RUN DOWN from repeatedly trying to start the mower with it.!! yes?

and finally but certainly not this....this is one of those universal size fits all shade tree mechanics methods to check and engine isn't borked...it will not tell you what the problem is, but it helps you eliminate many other things

remove all spark plugs...rotate flywheel BY HAND. Engine should rotate easily with no resistance. If it doesn't, you know you have something related to engine (valves, auto compression release, bent valves, valves stepped out or damaged, borked crank, seized or broken piston/piston rings, failed or borked PTO (is belt under tension all the time?, even power off?)

hopes this helps....start with the simple things and work up to the harder things...in most cases, especially if mower is old, it's going to be a simple thing...like wiring that has corroded or a starter solenoid that

 

[T-Bbone]

If you are sure the valve clearances are correct, and may want to double check to confirm. then next step would be the camshaft due to a broken compression release. And the washer would have been on the outside not behind for a shim. If it even was supposed to be there, unless that washer came from someplace else.

I have the same problem with the 270000 model. How hard is it to fix the compression release? If I take off the oil fill cap it shoots oil a foot high. I was going to replace the head (valve last was properly adjusted at some point the sleeve came loose and the prior owner pinned it back in place, so that sounded like the culprit) but it sounds like the compression release is the more logical source of the problem. Everything else on the mower is perfect so I’d hate to scrap it.

 

[biggertv]

Needs a Cam. been there, done that.

 

[Freddie21]

I think the Briggs single cylinder engines have two different starters. The gears have different amount of teeth. 14 and 16, if I remember correctly. They have to match the flywheel gear which can be aluminum or steel. Wrong gear and you'll tear it up.