91 force 120 will not start

[HMC49]

So I changed the lower end gear oil today, put some fresh gas in and the engine starts cranking. Cranks like normal before starting, but it does not turn over. Try again and it barely will crank. The battery was charged. Buddy of mine thinks it might be a solenoid or voltage regulator. Any advice.

 

[MJS]

Re: 91 force 120 will not start

Try a known good battery. Even if you charged the battery and it showed that it was charged, an old battery will only last a few seconds if its going bad.

 

[HMC49]

Re: 91 force 120 will not start

Ok I'll try that, probably time for a new battery anyway. I also tried to jump start the battery with my truck and it didn't help.

 

[pnwboat]

Re: 91 force 120 will not start

Maybe a corroded battery connection or a bad battery cable?

 

[canter6]

Re: 91 force 120 will not start

Did the boat run before the work? how long before? been sitting up for awhile?



FWIW,
I just ran through my force recently with a very similar problem,

every engine needs 3 things to run fuel,spark, and air.

check your plugs for spark with one of those 10$ advanced auto spark testers, while you're at it check your compression as well.
If you have sufficient spark make sure youve got fuel getting to the carbs, and into the motor (theres a great sticky on carbs in this forum) Ive read, although never tried using a timing light to check fuel spray patterns.

as for the air part, i wont say disregard, but seeing as these engine dont have filters to clog, its "fairly" safe to say this wouldnt be one of your issues.

starting there, should help you narrow down where to start looking, and avoid tossing parts at it aimlessly.

C6

 

[HMC49]

Re: 91 force 120 will not start

It basically sat all winter. When I first tried starting it, the flywheel? was turning very strong, engine sounded like it wanted to turn over. It didn't start so I give it a minute and tried starting it again, flywheel is barely moving, and it sounds low on power. A buddy of mine is a whiz with engines and gonna stop by tomorrow. I post again if we figure it out.

 

[canter6]

Re: 91 force 120 will not start

from what you just said, sounds like the batt, could be low on juice, as far as the slow start.

as far as the firing off, if it sat all winter with fuel in the carb bowls or tank, the gas might be bad.

What i did on mine was buy a cheap dollar store squirt bottle that i put a splash or the fuel mix in, and squirted into the carbs directly then tried starting again. (i did this after i confirmed i had spark)

It fired right up, and while it ran pretty terrible, once the fresh fuel i put in began to run its course it seem to free up whatever gunk mightve built up from it sitting up.

If the motor fires off, from the squirt, look into the carbs/fuel line/filter.

good luck!

 

[HMC49]

Re: 91 force 120 will not start

Its the battery. I hooked up the charger to it, and was able to get the engine started. The battery won't start the engine when off the charger. My old battery is 1000 cold cranking power, do I need one that strong for a 120HP?

 

[canter6]

Re: 91 force 120 will not start

great news!
as for the cranking amps, not 100% certain, if i can remember to, ill see if its in my digital manual when i get home, unless someone beats me to it.

 

[jerryjerry05]

Re: 91 force 120 will not start

A 1000 is too much.It can be used.
They only require a 450/550CCA
Remove the plugs and do a comp test.

 

[Jiggz]

Re: 91 force 120 will not start

I used 650~750 CCA. The question though is to make sure it is either a marine or deep cycle battery. If it is a regular starting or cranking battery, everytime you put the boat in storage and the battery is not on trickle charge, it will kill the battery. Which is not the case for marine or deep cycle batteries. Costco's kirkland brands are not too bad for $80 you can get a marine/deep cycle battery with a 750 CCA.