Loss of upper Rpm WOT 3000

[Derric]

90hp Mercury 2 stroke inline 6 replaced 2 swichboxes, kitted fuel pump and carbs, and replaced fuel lines all the way to primer bulb. Stator checks out ok shows running full power on Dyno but put it in the water 3000 WOT no upper end power is it possible stator is giving a false reading until its put under a load. It kind of acts like it is running out of gas in a way. I dont know. any ideas out there?

 

[Laddies]

Re: Loss of upper Rpm WOT 3000

The stator and the electrical parts are not effected by load with the exception of spark plugs, however they are effected by heat and a stator will break down from it, in some case you can lose 3 cyls. or in others the engine will lose spark completely. If you have a induction tach you can ck each cyl. for fire under load. Have you checked the plugs for water some of the inline 6 cyls have a plate and gasket immediately outside the exhaust ports and if the plate or gasket is damaged (usaully heat) it will allow the engine to suck water back thru the exhaust ports and it will drive you nuts, it don't happen often but it will drive you nut when it does.

 

[Derric]

Re: Loss of upper Rpm WOT 3000

Those damaged gaskets would cause it to have loss of power also huh? Well, how about this the stator wires that connect to the rectifier are bare insulation has cracked off where they connect to the rectifier and the rectifier looks corroded or rusty. I wrapped the wires with black tape but ya know that boat is almost 24 yrs. old and im sure the motor has all original parts except for the 2 switchboxes and 1 coil that I know of. What do ya think?

 

[Derric]

Re: Loss of upper Rpm WOT 3000

Boat runs good now replaced the stator.