Engine bogs when PTO is engaged **FIXED**

[JD_Driver]

Here is one for the masses
Lazer Z, Triton 66, 30hp
When PTO switch is engaged, engine bogs
just for a second or so just after activating the switch. It doesn’t die, but seems close. Within about 1-1.5 seconds, it resumes normal rpm.

New air filter, fuel filter, gas is good, checked for a bad coil, no issues there either. Cylinder pressures check good and they are even at 171. Checked spindles and idler pulleys with belt off, smooth, no binding.

Could the PTO clutch be engaging too quickly causing the bog? Any thoughts what to look for?

 

[bertsmobile1]

Two things will cause this
1) blown head gasket on one cylinder
2) Running on one cylinder

 

[JD_Driver]

Two things will cause this
1) blown head gasket on one cylinder
2) Running on one cylinder

I’ve thought about that. Pulled one plug wire while it was running. Bogged for a split second but kept running, same for both cylinders. Checked cylinder pressures and they seemed good. I’m not losing oil, no evidence of external leaks.

 

[JD_Driver]

Two things will cause this
1) blown head gasket on one cylinder
2) Running on one cylinder

You actually may have nailed it. I paid attention to a few things and I’m getting kind of a puff puff sound when I stop the engine almost sounds like an exhaust leak but it’s more of a puff. Can’t tell where it’s coming from.

 

[bertsmobile1]

The gaskets usually blow between the cylinder & the push rod tunnel
Cheap test is to remove the dip stick tube just after the engine stops
Wafts of light grey smoke confirm an internally leaking gasket .

 

[JD_Driver]

I believe I and going to get two head gasket kits. I believe you are correct with a leaking head gasket idea.

Thanks for taking the time and the suggestions. Appreciate ya

 

[mechanic mark]

Check air gap at PTO Clutch 3 places, should be 0.012" to 0.015".

how to check air gap at pto clutch - Google Search

 

[JD_Driver]

I’ll try that as well

Thinking more about it being a head gasket
When it’s been ran a while, good and warm, it bogs much less

 

[JD_Driver]

Air gap was big…….

 

[JD_Driver]

Ok…..so I think I’m set.

I did a compression test and it was acceptable. After changing plugs, I noticed they carboned up very quickly. I also noticed a few videos about bad head gaskets, guys spoke of a puff, puff sound when the engine stopped.

I decided to take the advice of a few here and get a gasket set. I did #2 first, crap sake, it had a snail trail leak. While it was tore down, I pulled #1 head as well. It did have a leaking area as well. The gaskets I installed were the new style.

I noticed the puff sound when engine is stopped is gone. My issue with the bog is greatly reduced as well, nearly nothing.

If I throttle it down to about 3/4 and engage the PTO, it engages very smoothly. Then I throttle up.

Will know a bit more when the gov idle spring comes in. Previous owner had it on the "least sensitive" position. I was going to move it to the factory setting hole and dropped it. Can't find it….searched for an hour, still did not find. I had guess the best way to find the spring would be to order a new one, however, that didn’t work, so I am waiting.

Thanks for all those who provided input and suggestions, greatly appreciated.