Weird issue, cart won’t stay running

[CP241]

Start with the basics :)

You can "rent" a compression tested from most auto parts stores for free. Just leave a deposit and they'll refund it when you return it.

There really isn't a whole lot to these motors. They're really pretty basic, but it's helpful to have a whole picture when trying to help over the internet

If compression is good we can check some other things. But its best to not assume anything and start fresh:)

[Largemouth21]

Originally Posted by CP241

Start with the basics :)

You can "rent" a compression tested from most auto parts stores for free. Just leave a deposit and they'll refund it when you return it.

There really isn't a whole lot to these motors. They're really pretty basic, but it's helpful to have a whole picture when trying to help over the internet

If compression is good we can check some other things. But its best to not assume anything and start fresh:)

My boss is going to rent a compression gauge next time he is in town. Until then, what are some other things I can test? I don’t understand how it decides to only run sometimes. Fuel is the only thing I’m 100% positive of

[CP241]

Auto zone, oreilly, etc rent them for free. You pay 50 bucks or whatever to use it and they refund it 100% when you return it.

I've got a suspicion your compression is low. But id want to confirm im wrong before diving in deep

[Largemouth21]

Originally Posted by CP241

Auto zone, oreilly, etc rent them for free. You pay 50 bucks or whatever to use it and they refund it 100% when you return it.

I've got a suspicion your compression is low. But id want to confirm im wrong before diving in deep

Welp, you were right 58psi in one cylinder and 60 in the other, I wonder why it ran good sometimes.... not sure how accurate the gauge is though

[CP241]

Make sure you hold the throttle at the carb wide open with your hand while cranking. Don't rely on the pedal, the cable being out of adjustment may not hold the throttle wide open with the pedal...

Also, double check the valve lash. I know you already said you set it, but I use .004 on all 4 of them. You'll have to rotate the engine over a half rotation to set the 2nd cylinder. And pay particular attention to the 2 valves in the middle (intake) they're known to wear so if you have considerably more threads showing on top.of the adjuster lock nut on those vs. The exhaust valves on the outside, you'll need to replace them. Once they're worn your compression can suffer, despite nothing at all being wrong with the bottom half of the motor.

If you're unsure what I'm describing just post a picture. Many of us can tell at a glance if they're worn or not.

[Cartmaster]

On these engines, As CP has already stated. The first thing i would have done was a compression check. You have found it very low, which suggests worn intake valves rather than ring wear or valve guide seals as you have not mention a smoking exhaust. Severe wear on the valves will drop compression drastically and cause poor starting and fading out on power.

One question. Is there oily residue in the air filter box?

As CP said, show us a picture of the lash adjusters. We like pictures LOL.

[Largemouth21]

Originally Posted by CP241

Make sure you hold the throttle at the carb wide open with your hand while cranking. Don't rely on the pedal, the cable being out of adjustment may not hold the throttle wide open with the pedal...

Also, double check the valve lash. I know you already said you set it, but I use .004 on all 4 of them. You'll have to rotate the engine over a half rotation to set the 2nd cylinder. And pay particular attention to the 2 valves in the middle (intake) they're known to wear so if you have considerably more threads showing on top.of the adjuster lock nut on those vs. The exhaust valves on the outside, you'll need to replace them. Once they're worn your compression can suffer, despite nothing at all being wrong with the bottom half of the motor.

If you're unsure what I'm describing just post a picture. Many of us can tell at a glance if they're worn or not.

I had the throttle all the way open, and I did notice one cylinder seemed to “bleed” the pressure faster than the other. Do you think that could be a sign of a valve issue? It doesn’t smoke when I can get it started so I think maybe it’s a valve issue

[Largemouth21]

Originally Posted by Cartmaster

On these engines, As CP has already stated. The first thing i would have done was a compression check. You have found it very low, which suggests worn intake valves rather than ring wear or valve guide seals as you have not mention a smoking exhaust. Severe wear on the valves will drop compression drastically and cause poor starting and fading out on power.

One question. Is there oily residue in the air filter box?

As CP said, show us a picture of the lash adjusters. We like pictures LOL.

I think you’re right, I just don’t understand how it can run good for a few seconds and even drive for a while (I went about 1/4 mile) and then just sputter out and not restart. I’ll post a pic of valves

[Largemouth21]

Here’s the head, about 2 threads showing on each
Can somebody please explain how a motor can run fine for a while if thexompression is really the issue? I got it to start and run fine for 1/4 mile but idk I’d it was full power or not, Cart is new to me

[Largemouth21]

Originally Posted by Cartmaster

On these engines, As CP has already stated. The first thing i would have done was a compression check. You have found it very low, which suggests worn intake valves rather than ring wear or valve guide seals as you have not mention a smoking exhaust. Severe wear on the valves will drop compression drastically and cause poor starting and fading out on power.

One question. Is there oily residue in the air filter box?

As CP said, show us a picture of the lash adjusters. We like pictures LOL.

Thanks for the help, I just posted a pic, there was a weird watery black/brown liquid in the air box, but wasn’t oily, I just removed the air box to work on it