50 hp 1972 johnson.. takes for ever to get to wot.

[bagnallt]

Hi guys...
I have a problem, yes another problem, with this 50 hp....
It starts and idles ok. You can increas the speed and revs to midrange when on the water ut when you go for hig speed it some times will go straight up.. like a hole shot. but when really warmed up it tkes for ever to get to high revs. lit doesnt bog down or loose revs it just takes a long time for the revs and the power to increase.. I checked with the cowl off and the throttle moves to wide open but it then takes for ever to for the coresponding increas in revs and increase in speed.
I checked the compression ... hot and cold sompression was 120 top 118 bottom. I have a good spark at idle. I have replaced the sprk plugs rebuilt the carbs. I have recently replaced a coil, replaced the stator, new feul pump.... One thing i have noticed is that the feul filter ( its glass) at times is only half full with gas.... could this cause the problem .. ( a clogged fuel filter?) The peimer bulb stays firm and doesnt colapse

ANyway .. all suggestion are appreciated

 

[The-Machinist]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

Im afraid that you might still have some junk in the carbs. Or maybe a coil failing under load. I have the walmart glass fuel filter mounted before the engine and it is sometimes full, some times not. Either way it doesn't affect the performance of "my" motor.

 

[jay_merrill]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

The fuel filter won't remain full of fuel as the motor runs, just as a squeeze bulb won't either.

The fact that the motor runs better cold than hot, makes me suspect something in the ignition. Sometimes power packs start acting up when they get warm, but I think the usual symptom is obvious misfiring of one or both cylinders.

I'm not sure that I'm on the right track but just in case - does the motor run better with the cover off? If so, you may be leaking exhaust gases into the cowl via the electric shift wire on the port side of the motor. This is a common problem in 1972 hydro-electric motors. Regardless of if it is what is causing your problem, if you notice exhaust leaking up through the hole in the midsection, where the wire passes through, you need to seal it. Just remove the ring section under the cowling and apply some heat resistant silcon around the wire at that hole.

 

[tashasdaddy]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

also link and sinc, make sure the timing plate is moving, it the timing is not in sinc with the carbs, you get bad performance.

 

[bagnallt]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

thanks guys...
I will firstly check the seal around those wires. and seal it anyway. I replaced one coil with a new one so i will change out the other. Hopefully it will work.
My wife ... said she though there was a slight missfiring during the time it does this trick but then when it gets to high speed the missfires stops and as long as you keep the throttle up there it runs great with no missfire...
Would sucking the exhaust gas into the engine casue a misfire at midrange and not at top??
thanks guys....

 

[bagnallt]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

as per link and sync....
when i move the throttle forward i see the timing plate arm move and the throttle plate linkage move in the carbs. it seems that the throttle plate on the carbs reaches wide open quite a bit before the timimng plate reaches full travel. I dont see in the manual (clymers ) link and sync but i will look again .... Am i right in assuming it should reach the end of its travel the same time as the carbs reach wide open???
Thnaks again....

 

[bagnallt]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

deleted double post

 

[tashasdaddy]

Re: 50 hp 1972 johnson.. takes for ever to get to wot.

you have a PM.