Honda gx390 engine ticks, burns oil, 72psi compression.

[Oil pan 4]

Already did the value lash. Ain't the valves. The engine is old, like 20 years old, has the old style cyclone air cleaner. Air filter was improperly installed and was sucking in some dirt when I bought it for $50.
It was an air compressor most of that time. Then I got a hold of it gave it a good tune up, set valve lash, found a seal missing in the carb, put in a smaller air bleed plug and main jet, took the main jet from a 104, to a 100 and then to 95.
I put it on a stump grinder and it was a stump grinder for a few years, now it's a wood chipper. It will probably end up as a pressure washer eventually.

What do you think.
Is the piston rattling around in the bore?
Excessive rod bearing clearance?
Edit: there is no rod bearing, just aluminum.
A new one like this is about $800.
A predator 459cc was about $500 two years ago, after tax with a 20% coupon.

 

[jkrubi12]

I've got a Honda snowblower and the engine makes all kinds of extra noise; I think the engine is a GX390. Every season I wonder if it's going to come apart but it just keeps on ripping on....The oil looks fine as well, never figured out what the source of the noise is.

 

[PoTreeBoy]

Already did the value lash. Ain't the valves. The engine is old, like 20 years old, has the old style cyclone air cleaner. Air filter was improperly installed and was sucking in some dirt when I bought it for $50.
It was an air compressor most of that time. Then I got a hold of it gave it a good tune up, set valve lash, found a seal missing in the carb, put in a smaller air bleed plug and main jet, took the main jet from a 104, to a 100 and then to 95.
I put it on a stump grinder and it was a stump grinder for a few years, now it's a wood chipper. It will probably end up as a pressure washer eventually.

What do you think.
Is the piston rattling around in the bore?
Excessive rod bearing clearance?
Edit: there is no rod bearing, just aluminum.
A new one like this is about $800.
A predator 459cc was about $500 two years ago, after tax with a 20% coupon.

It also has a gear-driven balance shaft that could be contributing.

 

[L35]

My Kawasaki 2 cyl 23hp on the zero turn ticks like sloppy valves. Adjusted the valves and they were fine. Been doing it since new, I guess it’s just how it sounds.

 

[Oil pan 4]

It also burns oil. I figured before it was burning oil because it was a stump grinder and I was tilting the engine too much. Nope it just burns oil constantly. Worse at idle, not much when it's running hard.

 

[Runs With Scissors]

I have had 2 Honda engines in the past, both of them needed valves and valve adjustments so often, I was hoping someone made a "Auto-valve shim-button". I never did find one.

This attachment fixed them both though.

Then I started buying Yamaha....Sorry, I couldn't resist....LOL

 

[Oil pan 4]

Not a bad idea, I would like an electric start.

 

[Oil pan 4]

I did a compression test, it has about 72psi cold and about 78psi hot.
Well, it's easy to pull start.

 

[#40Fan]

I'd be happy that it has lasted this long and just keep on filling it with oil and run it.

 

[Oil pan 4]

I filler up with oil and I get about an hour of run time before the low oil shutoff kills the engine.
Burns a lot of oil.

 

[#40Fan]

Ah, one of those, check the gas, fill it up with oil engines.

Rip it open and check the bore, piston and rings. See if anything can be replaced to bring it back into tolerances.

 

[Oil pan 4]

I took it out of service and replaced it with a predator 459cc from China freight for about $560 out the door.
This weekend I'll at least get the head off the old gx390 and see how bad the bore taper is. If the weather is nice I'll pull it apart and see what else it needs. Side bearings, connecting rod, crank.
It would make a great pressure washer engine.
I'm thinking if the block needs bored just get a 90mm electric start engine block and 90mm piston kit. The original engine is 88mm, so going to 90mm would make it about a 408cc.
If the stock 64mm crank is worn out put a 66mm predator 420cc crank and rod in it.

 

[Matt Ellerbee]

I took it out of service and replaced it with a predator 459cc from China freight for about $560 out the door.
This weekend I'll at least get the head off the old gx390 and see how bad the bore taper is. If the weather is nice I'll pull it apart and see what else it needs. Side bearings, connecting rod, crank.
It would make a great pressure washer engine.
I'm thinking if the block needs bored just get a 90mm electric start engine block and 90mm piston kit. The original engine is 88mm, so going to 90mm would make it about a 408cc.
If the stock 64mm crank is worn out put a 66mm predator 420cc crank and rod in it.

It’s jealous of your tractor, turbo it.

 

[Oil pan 4]

The old Gx390 had plenty of power for a wood chipper.
Before it was on the wood chipper it was on my stump grinder and it was scarry. The 459cc powered stump grinder is unstoppable.

 

[GreensvilleJay]

OS piston and ring kit will be $200-$250, few gaskets and such.. more than 1/2 way to a new engine,even when not on sale. Not sure if I'd fix it. You could have 300 into it and next day, some other $$$$$ part would fail !