losing revs, misfiring?

[doctorbob]

Ok gave boat a run today after a $500 service and still have the same problem as before service/ tune up/ repairs. Engine loses revs at high speed around 4500 to 5000 rpm and coughs and splutters but runs ok at low speed/ revs. Had plugs and top gaskets on gearbox done and mechanic said ran well in workshop on the muffs. Reckons it may be coil related and faulty at temperature. I'm not saying repairs weren't done that he found but is there a way to check coils under load/ temp to see if their faulty. Don't really want to spend another $500 if its not the problem. Motor is 75 hp merc 2 stroke, which was not firing on top cylunder prior to repair
Rob

[Fed]

See what happens when you hijack someone's thread then let it run for a while then start a new thread about the same thing... no one knows wtf you're talking about. I feel better now.

Stop the water getting into your tank.
Tilt your boat up as high as it will go.
Drain & flush the tank, fuel lines, trap, carbies and replace all filters.
Metho is your friend with this.
Refuel & go fishing.

[Spaniard_King]

Time to upgrade

[doctorbob]

Think your right Gary although I did find a clamp missing off fuel line going into motor, was quite loose hopefully this may be the culprit
Rob

[bf90]

Time to upgrade

And make sure it s a HONDA!!

[doctorbob]

Point taken and thanks for your constructive criticism fed. Netted problem out today and found blockage in fuel line caused by inner rubber lining of fuel hose pushed back in on itself blocking line. Motor ran fine on aux tank
Rob

[Fed]

Good news Doc I hope you're on a winner with that.
At the very least I'd still be looking at where the water is getting in and draining / flushing the system at least up to the motor.
Any water in the trap is a worry.

[doctorbob]

Boat sat for 3 weeks empty after I had welding done. I am assuming I got a lot of condensation as its about 90 litre tank I think
Rob

[Fed]

You have a leak Bob, either that or everyone else in Qld got the same condensation in their tanks too. Did you get any in your car tank?