Engine dies under a load

[Paradise pontoon]

Hello have a 1984 Johnson 150 V6. Replaced all fuel hoses,fuel filter, rebuild carburetors,replaced spark plugs,drained fuel tank and added new fuel, replaced primer bulb, and checked fuel pickup tube screen. Timing is 8 degrees at idle and 32 at 5000 rpm. Engine runs great without a load on it. Tried electric fuel pump didn’t charge anything.
Thanks

 

[racerone]

Post the actual compression test values.

 

[Paradise pontoon]

Post the actual compression test values.

All 70psi

 

[cyclops222]

Has this engine been running great for years ? and suddenly in 1 run developed this complete collapse of power ? Yesterday great. Today nothing ?

 

[cyclops222]

UUUHHH I think someone forgot to use the correct oil ? Or no oil ?

 

[racerone]

Well----70 PSI is way too low.----Should be around 120 PSI.-----Time to remove a cylinder head for inspection.-----You may not like what you see.----Post pictures when head is off this motor.

 

[saltchuckmatt]

Next time start with the compression check

 

[racerone]

It is a substandard gauge or a motor that needs major work.

 

[Paradise pontoon]

Post the actual compression test values.

All cylinders have 72 psi

 

[Paradise pontoon]

Next time start with the compression check

I did sir

 

[racerone]

???----That is way too low !!!!!-----We can not see , hear or touch your motor.-----You are reporting compression values tested by you.-----And they indicate motor needs lots of work.

 

[Paradise pontoon]

It is a substandard gauge or a motor that needs major work.

Really? I thought of that! Didn’t need smart ass comment!

 

[racerone]

Just stating facts as reported by you !!

 

[Paradise pontoon]

???----That is way too low !!!!!-----We can not see , hear or touch your motor.-----You are reporting compression values tested by you.-----And they indicate motor needs lots of work.

72 in specs with Johnson the year model

 

[racerone]

Well----Good luck with your motor !

 

[Paradise pontoon]

I’m sorry just really frustrating

 

[Paradise pontoon]

Has this engine been running great for years ? and suddenly in 1 run developed this complete collapse of power ? Yesterday great. Today nothing ?

No has been setting for years. I don’t know any history on the boat. We changed gas again with different oil mix. . Still the same. It runs very well with no load on it. Soon as you put it into gear and prop engaged it dies I pulled lower unit off and checked it out and all seems good

 

[Paradise pontoon]

Could it be a coil pack or stationery?

 

[Chris1956]

Gee, sounds like the carbs. Put a flusher on the motor and give it a shot of 50::1 down the carb throats. Crank it up, choke closed and see if she runs a bit. If so, the carbs likely need cleaning.

 

[saltchuckmatt]

Most motors will run good underload because they are ....underload.

Your motor is mechanically shot. Rebuild or buy something else. Tough lesson but your in a very large crowd.