Mercruiser 5lt EFI problems at planing speeds

[Geoff66]

Hi, I've got a Searay 215, a 2000 model, which has a Mercruiser 5lt EFI motor. It starts on the first turn, it runs as sweet as can be and when pottering along at low speeds it never misses a beat, then all changes once it gets going.... I was on the plane for no more than 5 minutes yesterday, at about 30mph, when the engine starts stuttering and almost stalling. I backed off to 6-8mph, and a few stutters later, it was happily pottering along again. It's just had a new impeller fitted, was recently serviced, has new risers. Any suggestions as to what I should be looking for ?? Thanks in advance for any help, Geoff

 

[wipe_out]

Sounds to me like fuel starvation.. Maybe replace your fuel filters (if not already done) and make sure the fuel pump is working properly and delivering enough fuel at the right pressure..

 

[julians]

Could be fuel as per comment above,but also check the spin on fuel filter is on tight,if it's not fully tight you can suck air in with the fuel.

Also when was the last time the distributor and ht leads were replaced? I had an issue with my 5.0 mercruiser at higher speeds and it was down to corrosion in the distributor

 

[Richardcm]

Well worth removing fuel filter and upending its in a clean bowl and see if theres any water/rubbish in it, got water in my vp 4.3 caused loads of aggro until I sussed it was water.
As Julian says above the v/p dizzy also corrodes inside