2000 Johnson 90

[xtreme872]

I have a 2000 Crest pontoon.. with a 2000 johnson 90... when riding the engine all of sudden speed up and slow back down... Mechanic changed plugs last yeat but still does it... seems like its worse after riding for awhile and at lower speeds... Almost seems like ignition trouble... I am no boat mechanic though.

[Silvertip]

More than likely the problem is fuel or spark related. My guess is old fuel, water in fuel, fuel pump going bad, gummed up carburetors, clogged or partially clogged fuel filters, to name a few. When this is happening, squeeze the primer bulb a couple of times. If the engine smooths out, you have a fuel problem that is probably due to a weak fuel pump.

[tashasdaddy]

those motors have 2 piece cam follower roller, the outside part of the roller is known to crack and fall out, leaving play in the throttle/timing linkage. this may be your problem. just found a bad one, on a motor yesterday. see the screw with roller, left center of this picture, it is complete. has black inner and white outer part of the roller.

[xtreme872]

It also feels like when the motor is wide open its not running wide open. Also boat was winterized each year by mechanic and whole new tank of fuel put in this year...where are and how many fuel filters on this motor

[tashasdaddy]

should be one on motor, maybe a fuel/water separator, between tank and motor.

[xtreme872]

do you think it could be a power pack goin bad?

[tashasdaddy]

until you trouble shoot it, there is nothing certain. i agree with the advice above.

[xtreme872]

i will change filters and try again next weekend... and go from there.

Thanks for all the help

[Dhadley]

Don't be confused by that picture. Your motor doesn't have that type linkage.

[xtreme872]

anyone know how many filters/water seperators there are on this engine and where? Fist time working on it but I am mechanically inclined

[xtreme872]

I cleaned the fuel filter.looks like brand new and have run more than a full tank of fuel through... I think it may be ignition related.. whats the best way to check the power pack... or should i start somewhere else first

[xtreme872]

also prop has a few chips... so i was looking into a new one... and sunday with 4 people wide open i was only at 4200 rpms...