91 50 hp force died

[burbl]

i have a 91 50 hp force, it has a new lower unit, a new stator. the carb was rebuilt and the fuel pump was rebuilt. driving out on the lake and it died. i have spark and i have fuel but it will not start, it cranks over and backfires out the exhaust and that's it.. any ideas... thanks from burbl

 

[jasperpso]

Re: 91 50 hp force died

i am admittedly a novice, but it sounds like a timing problem to me? thats were i would start.

 

[roscoe]

Re: 91 50 hp force died

you have fuel and spark, the only thing missing is compression. Do a compression test. If low on any cylinders, check the reeds.

 

[burbl]

Re: 91 50 hp force died

the cylinders comp is 105 each, as far as timing,what would throw the timing off, could the trigger be bad?? thanks for the help....burbl

 

[jasperpso]

Re: 91 50 hp force died

well, i am waiting on a service manual for the same engine, except mine is a '86. i would recommend to u the same as everyone did me, get a service manual, i got one for this engine for $23 so it is a good investment. I am sure it has the answer to you questions, and no question of accuracy(hopefully)<br /><br />jason

 

[12Footer]

Re: 91 50 hp force died

If you have spark on both, the ignition system in total is fine. In order to jump time, this motor's flyweel must shear it's pin. Otherwise, it cannot jump time. Comp is a tad low, but still adequate (unless they are both equal,in which case, i would thing the gauge is reading low).<br /><br />So it HAS to be fuel. Try this; get a clean spray bottle ,and put some mix in it. Spray 4 or 5 good shots of fuel right into the carb body, and crank it.<br />If it spits, sputers or briefly runs, your problem is fuel delivery.

 

[burbl]

Re: 91 50 hp force died

sprayed some fuel in the carb and it still does the same thing, it acts like it wants to start but it wont, i checked fuel pumping to the carb and it is very good, i went thru the carb and could find nothing wrong, it does act like the timing is off, but like you said it has to shear the keyway, i had the flywheel of it this morning and everything looked good, could it be the trigger that would throw the timing off or the cdi. i still have spark but it may not be on time. thanks for the help so far...burbl

 

[12Footer]

Re: 91 50 hp force died

<br />I'm begining to suspect water getting in the jugs.<br />It would cause the backfiring too.Not much else can cause that iether ,except for timing, fouled plug, contaminated fuel (water), or a lean condition at hte carb (plugs would be dry).<br />Pull the plugs and see if they are wet. If they are, is it from gas, or water? Any signs of surface rust? This could indicate a cracked block, or warped exaust port plate,or plate gasket, water in the carb bowls and consequently, the fuel tank, or blown exaust port plate gasket.<br />A used plug would look very new because it got steam-cleaned when the water intrusion occured. I would think the head gasket was leaking by, but compression is pretty good and equal, so chances are slim it's head gasket. Most common in the monsoon season is water getting into the fuel system,so check that first, all the way to the carb bowl.