2000 Mercruiser 5.0 Thunderbolt 5 Ignition idle issue.

Yannih

Cadet
Joined
Aug 28, 2023
Messages
18
Well, we have been using the boat and it is going great guns after the advised adjustments here!
While all is now good engine wise on all levels re cold starting, power transition and delivery, idle and consistency, it does seem to be going through a fair bit of fuel.
Quite a bit more than my old 1998 Four Winns Horizon 190 that had a Volvo Penta 5.7GL engine.
Any idea's on what may be happening or what I should check?
P.S.
Yes we run at near full throttle at times for in-efficient fuel economy, but no more than the old boat that didn't seem to have the same fuel burn rate.
Thanks again all in advance for any advise forthcoming...
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,064
Check the plugs, if all are black then it's getting to much fuel or timing is way off

If plugs look good, then it's just HP to weight thing.
 
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