I have a 2012 90hp mercury optimax tiller. It runs great at half to 3/4 throttle but once I go full throttle after a few seconds it like shuts me down to half speed than I have to let off the throttle and than go again. Is this a fuel issue or spark or???????? Any help would be great thanks.
It sounds like it’s going into “limp home” mode – how’s your water temp? Maybe need a new water pump, unless a sensor has gone bad.
Sounds like it starved of fuel. Check your fuel filter and/or the fuel water separator if equipped. Also the fuel tank vent make sure it’s not clogged.
Thanks guys keep em coming I will try them all.
Sounds like it starved of fuel.
Agreed. Limp mode will usually limit the engine to a certain RPM/possibly shut down cylinders and won’t go away until that grounded problem goes away.
When I replaced my fuel pump not long ago had almost same issue, could run up to 3800rpm just fine but WOT after 75yds or so engine would seem like it go into limp mode. Got big bowls on my carbs so could go quite a bit before she starved. Mine was air leak in the new fuel pump.
Haven’t moved any internal hoses lately by chance? Maybe screwed in any hardware?
Have heard of bad plugs acting funky at higher rpms, cheap try. Coils going bad perhaps. Got any goo leaking around any of them?
Would definitely eliminate any kind of fuel air issues first, that’ll really hurt a cylinder!
Good luck, keep us updated.
Check your fuel line. Some fuel lines delaminate on the inside from ethanol.
Fuel injectors?
Thanks guys I will start with the fuel filter and water separator also I will try replacing the fuel line.. than I will move on to plugs and coil packs.
You must be logged in to reply to this topic.
