Reply To: Struggling under load

[Don]

Well, OMC did make high altitude kits for these engines, which included smaller high speed jets… But, you mention that the engine lurches ahead momentarily, so I’m thinking there is something wrong…Does it seem to pick up RPM for that second? I know you mentioned checking spark and it was OK, but perhaps the engine is losing spark to one cylinder at high speed settings…You might want to try using those inline neon testers, then you could monitor them while and assistant drives the boat at WOT. Did you try replacing the plugs again? Just cuz they might be new, doesn’t mean they are any good…
Any chance of you posting a video of the engine misbehaving?