85 Force delayed stall at WOT

adamkat22

Petty Officer 2nd Class
Joined
Jul 12, 2015
Messages
139
I have an 85 Force that seems totally fine for the first 20 -30 min at WOT and then suddenly it bogs down. If we take the throttle down quick enough you can idle and chug along just fine forever. If you don’t throttle down soon enough…it stalls.

Seems like if you wait 5-10 min with the engine off and start over it’s good for another 30min. If you just idle for 5-10 min (as opposed to fully shutting off) it will stall within a few minutes after starting.

Shorter rest periods means shorter time it will stay at WOT.

So far have just replaced the fuel line from tank to engine (seemed like it had some kinks in it). Unfamiliar with this fuel filter but screen looks clean?

Looking for any suggestions on next trouble shooting steps.

Thanks!
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
I just had the almost identical experience with my 125HP and always thought it was overheating. Replaced the impeller and thermostat but the problem persists. The noticed the clear fuel filter after the fuel pump and before the carbs is filled solid with fuel. So I replaced the fuel filter thinking it was limiting fuel to the carbs. The problem persisted although at the driveway, the motor runs smoother with the new fuel filter. But the next day it would not just start anymore. Had to use the small aux motor to make it to shore. At the driveway, I tried running it again but it was missing and using the drop cylinder diagnosis, #4 was the missing cylinder. Compression test indicated 30 PSI. Further inspection revealed a broken ring (as always caught on exhaust ports) and piston. My recommendation is to do a compression test first.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,037
After the compression test, check the overheat alarm? Key on, ground the orange lead at the buds bar, the alarm should sound off.
Then check the tank vent for a clog, bugs get in the hose and can cut off the air starving the motor.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,037
After the compression test, check the overheat alarm? Key on, ground the orange lead at the buds bar, the alarm should sound off.
Then check the tank vent for a clog, bugs get in the hose and can cut off the air starving the motor.
 

topgun3690

Lieutenant Junior Grade
Joined
May 7, 2019
Messages
1,034
This thread reminds me of some advice I got after swapping out my PH....the man from Sweden said "Maintain it well and not run the hell out of it". Great advice right there....
 
Top