intermittent reduction in power 2004 mercury60 four stroke

[pflugrad]

Engine occassionally reduces power back to idle without cutting off. Usually when cruising at or about 20 mph...never at lower speeds. Always resumes normally.

Engine is well maintained with recent 100 hour maintenance that also included replacing original fuel line and primer bulb.

Any clues?

How to trouble shoot?

What is my risk? That is, should I immediately seek repair or can I keep operating hoping that problem miraculously goes away?

Thanks

 

[woody66912]

Re: intermittent reduction in power 2004 mercury60 four stroke

Check your fuel pressure at the output of the fuel lift pump, that's the one mounted on the valve cover. If it's not showing 5 psi you need to replace it, It's not the diafram in the pump but the piston that rides in the pump housing when the oil gets the housing hot it does not allow the piston travel freely. when your on the water and it does it, go and squeeze the primer bulb I'll bet the engine will run fine until the vst tank gets low on fuel. sadly there is no rebuild kit for this pump. The pumps run about $100.00.

On a side note I have replaced five of these in the last two years at work.