Engine Power Complaint

[bartles]

Working on a Toro Model: 75754, Engine Model 139-0602

The complaints and observations are: when deck is engaged the engine "bogs" down almost to a stop but will regain rpm. Low power. Exhaust smoke. Oil in muffler outlet.

I did a compression test on both cylinders: both tested out 150-160 psi. Owner says he replaced carb?, new oil/filter. He says he has noticed slow increase in sump oil level in a 6+ month time period.(not sure if this was before or after new carb was installed.)

My next steps are to remove the flywheel cover to be sure the engine breather hose is intact and not leaking on the way to the fuel pump....,

I'd appreciate any and all suggestions...

Thanks in advance,

bartles

 

[StarTech]

Loncin 2P77F engine.

My lord the first thing is make sure it is running both cylinders.

 

[bartles]

Loncin 2P77F engine.

My lord the first thing is make sure it is running both cylinders.

Good idea!! It's not...all the time. I checked valve clearance on both cylinders....tight, zero clearance(set at .004"). The suspect cylinder does eventually fire (checked with a heat gun on the exhaust pipes) then dies in less than 30 seconds. The spark is very weak.

 

[bartles]

Did a leak down test....80psi in......dropped to 15psi. (I put too much faith in a compression test!,,)

I hear a leak coming from the push rod space.... a little at the carb, but none from the dip stick.

 

[StarTech]

You are learning....Just cant on one test. Even that even test needs to be modified to test the middle and lower cylinder areas which quite easy on an OHV engine. I have had engine to pass the standard leak down but the fail the modified test.

 

[bartles]

Well I did a leak down test... suspect cylinder, at 80psi inlet, is 20psi....there's you sign. Opposite cylinder is 75p Leakage is coming from push rod area and oil fill.

You are learning....Just cant on one test. Even that even test needs to be modified to test the middle and lower cylinder areas which quite easy on an OHV engine. I have had engine to pass the standard leak down but the fail the modified test.

Yep, slower means more methodical!! I need to get knowed up on "modified" testing.

 

[bartles]

Follow up....replaced the head gasket(1) and all was well until the new fuel pump failed to pump...and yes, it is a Amazon knock off. I took the diaphragm out of the new pump and replaced the failed diaphragm in the old pump...probably from excessive crankcase pressure.

Question: Are the OEM fuel pumps for $60+ any better than the Chinese knock offs?

 

[Auto Doc's]

I get them from Jack's small engine or a reputable supplier on Ebay. I do not recommend Amazon for anything other than cheap clothing.

 

[Douglas Lee]

I have some faith in Rotary parts . . .
Thanks,
Doug Lee
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