Loss of Power When Warm ST350 with EH35C

[KickersFirst]

I've got a 2001 EZGO ST350 with the EH35C engine and bypassed govenor, otherwise stock. I've done a lot of restoring but haven't touched the engine because it has always ran....Then 2 things happened....a few months apart.

First, I changed the oil and ran it a couple of times. While out on a ride, I noticed more smoke than usual and a slight loss of power. I checked the oil and it was low. Found out that when I changed the oil, I hadn't tightened one of the oil filter cover bolts enough and there was a slow leak. Put oil in and it was fine.

Fast forward a few weeks.... My brother took it out and rode it pretty hard, attempting hill climbs and some off roading, pedal to the floor all the time I'm sure.

Now, it starts up and drives but after it gets warm there is a significant loss of power. Almost to the point it won't move. Let it sit and it will start and drive for 100 yards and the same thing. I took it to my local cart guy and he said that since the Govenor was bypassed, over time that will jack up the valves (It has been 7 years). "you can adjust the valves again but the adjustment won't hold and it will go back to a loss of power. So I adjusted the valves and he was right. Lasted a few hours and back to loss of power.

So I guess it's time to rebuild the head (as recommended by the cart shop). Of course, if I'm going to do that then I may as well hop up the clutch and do the 295 head on the 350 block.

Does all this sound good or am I missing something?

[Gearhead1956]

What part in the valve train is your mechanic saying is the issue?

Would seem to me that if the valves will not stay adjusted, the issue would be in the rocker-arms.

May just need to replace the rockers. They do not come in the rebuild kits I have seen.

[KickersFirst]

He said the valves, maybe they get too hot? I took it apart and the rockers do have three slap marks like the cam contacts in three places as it engages the rockers. There is a pattern to the wear on the rockers, they aren't smooth.

[Cartmaster]

Inlet valves are known to be the cause of your issue. they will be very worn with very thin edges, almost like a serated knife. You will need to change these and use your judgement on the rocker gear as to whether you need to replace them. When you look under the valve cover, is there more thread above the locknut on the inner two valves? If so, there is your proof.
These engines when run on a bypassed or tightened governor, need an air tight filter system or they just suck in loads more dust and wear the valves like a gridstone.