Another No-Starter

[Nlb7928]

Fairtax4me, I think my valves are moving fine. They were functioning 2 days ago when I set the lash. I will start there though, just to make sure.

[CP241]

Originally Posted by Fairtax4me

That’s no fun. Really only one thing causes that. Either the cam gear wheel is stripped or the rovers that hold the gear to the cam fell out.

You should be able to verify by removing the rocker cover and turning the motor. If the cam gear is damaged the valves won’t move when the motor turns.

second that. Remove the valve cover and turn the motor over by hand. if the valves don't move then most likely cam is toast. The gear connecting the cam to the crank is plastic and held in with rivets. It can either strip the plastic or the rivets fall out and the gear spins, but the cam itself does not.

Also there is no jug on this motor. The engine case and cylinder are all one piece.

I do have a good used camshaft for a FE290 if that turns out to be what happened and you need one. It's not hard to replace it. If you've rebuilt the top end on an ATV before, it's no more difficult than that. Pull the clutch off, and remove a bunch of bolts on the side cover. The cam is right there. If it's at TDC and there's no tension on the push rods you shouldn't even need to pull off the head, just make sure the tappets don't fall out of the block when you pull out the cam. The hardest part of the whole job would be removing the motor. The 2 bolts in the rear of the motor bolting it to the rear end are kind of a PITA to get to, particularly the one behind the driven clutch.

[Nlb7928]

Originally Posted by CP241

second that. Remove the valve cover and turn the motor over by hand. if the valves don't move then most likely cam is toast. The gear connecting the cam to the crank is plastic and held in with rivets. It can either strip the plastic or the rivets fall out and the gear spins, but the cam itself does not.

Also there is no jug on this motor. The engine case and cylinder are all one piece.

I do have a good used camshaft for a FE290 if that turns out to be what happened and you need one. It's not hard to replace it. If you've rebuilt the top end on an ATV before, it's no more difficult than that. Pull the clutch off, and remove a bunch of bolts on the side cover. The cam is right there. If it's at TDC and there's no tension on the push rods you shouldn't even need to pull off the head, just make sure the tappets don't fall out of the block when you pull out the cam. The hardest part of the whole job would be removing the motor. The 2 bolts in the rear of the motor bolting it to the rear end are kind of a PITA to get to, particularly the one behind the driven clutch.

Do I have to pull the engine, or can the camshaft slide out while in there? I'll DM you if I need that used cam.

What if the valve's do move? What is second most likely cause?

[Fairtax4me]

If the valves do move when the engine turns, then the cam gear is probably OK.
I suppose another option could be a totally blown out head gasket, or a burned valve, but neither of those are very common. The heads on these are easy to remove though so that could be something that's easy enough to check out. Do you have an air compressor or access to a compressor? You could do a quick and dirty leak-down test using the compression tester hose if it has the right fitting on the end.


If it is something internal, The side cover can be removed with the engine in the cart. But if you ask me it makes it more difficult to do that way. And it's trickier to get everything lined up to re-install the cover. I'd rather pull the motor and put it up on a bench.
I don't try to separate the motor and trans in the cart, I disconnect everything and roll the whole lump (engine/transaxle) out from under the cart. Then everything is much more accessible.

[CP241]

You will need to pull the engine, yes. It's not that hard, disconnect fuel lines, belts, starter/generator. There's 4 nuts and bolts through the bottom, and 2 nuts on the rear of the engine through the plate. They're the 2 in the middle, one on the driver's side is pretty easy. The one on the passenger side you'll want to remove the driven clutch to get to them.

You said you have no compression. So either the camshaft is broken, the rings are blown out (Which is unlikely since it was so sudden) or there's a problem with the cylinder head/valves (bent valve, valve seat fell out, etc).

If a push rod fell out, the valve would be stuck closed (valves won't move, but you would have compression). There's a chance the head gasket has blown out, but you'd probably notice the excessive noise.

I did buy a Polaris 4wheeler once that had no compression. It must have sat in a barn forever because it was in MINT condition, and only had like 70 hours on it despite being 10 years old. I tore into it I found that the carb was NASTY (completely inoperable) and they must have tried starting fluid, and I'm guessing they used the red straw with the starting fluid. Because when I pulled the head to have a look, I found the straw stuck in the valve holding it open. I removed the straw, put it back together, and the thing ran like a top! So, there's always a chance something fell into the motor and stuck one of the valves open too...

I would pull the motor out, drain the oil, and start by taking off the clutch and side cover. Most likely it's going to be the camshaft, but truly the only way to figure out what is going on is to take it apart and see what let loose. It would have to be something pretty obvious going from a running driving cart, park it, to 0 compression overnight without some sort of (noisy) catastrophic failure.

[CP241]

Originally Posted by Fairtax4me

.
I don't try to separate the motor and trans in the cart, I disconnect everything and roll the whole lump (engine/transaxle) out from under the cart. Then everything is much more accessible.

Probably wise advice. I've never tried that. The one I have now I just unbolted it and pulled it out through the seat hole, but since the only thing really holding it in is the leaf springs and shocks, I'm thinking your method is probably a lot easier!

[Nlb7928]

Well, that's some BLEAK outlook right there! I will put some air to it tonight to see if I can hear or see any leaks, but I don't think I have a valve for holding pressure in the cylinder. But, I won't be able to do much more until next week. We are starting wheat harvest on our 3rd rate operation, so instead of getting dirty tearing into the engine, I get to have chaff and dirt blown on me for 12 hours a day for 3 or 4 days.

[CP241]

it's not that bleak. :)

Even the "hard way" I do it, I can still have the motor out and on the workbench in about 20-30 minutes at most. I pull it out whole with the clutch still attached.

And whatever is broken, as long as there isn't a big hole in the block, not that hard or overly expensive to repair. Just gotta find out what it is you need to replace first, and cant know that until you take it apart.

Good luck with the harvest They're just now planting the field behind my house this week.

[Nlb7928]

I popped the head off and found...the exhaust valve was not closing all the way. I got the valve out and it had carbon buildup around the stem. I scraped that junk off and re-installed everything. Runs like a champ!!

Two more quick questions.

How many torques (ft lbs) should I apply to the head bolts?

I'm leaving the black shrouds off the engine...change my mind.

Thanks guys for all your help! I really appreciate it!

[lockman1]

Good to hear that it was somewhat easy, time to use Seafoam in your fuel to prevent it from happening again!

Head bolt torque ~ 17.5 ft lbs,

Yes, put the engine and fan shrouds back on!
it's an air cooled engine, the fan on the flywheel will blow air through the cooling fins to keep it from overheating.