1989 Force 50HP Blues

[Gearboxz]

Ok long story short i recently boat a quantum bass boat with a 50hp Force. Wouldn't go over 10mph.. I inspected the prop and found it was bent. Replaced it and now get 21mph. So I rebuilt the fuel pump, replaced the plugs. Still doesn't get past 21mph. I know this motor will push this 15' boat faster then that. closer to 25-30

What I'm noticing on WOT is it takes some time for the RPMS to build up and get the boat up on plane as it barely planes at 21mph. This boat doesn't have a tachometer so unsure if its reaching peak RPM. The prop is what came on the boat which I replaced with a new one matching factory. My hunch is a improperly adjusted carb or dirty? As when you do a wide open punch the rpms come up slow, not super slow but not like other force 50 Ive seen where they get up and go. But as it gets to top end, it will miss once once in awhile. Not constantly like here and there and be fine for awhile. Checked compression and its 130 each cylinder.

Can anyone tell me where the air/ fuel mixture screw is , as from what I understand the screw on the front of this carb is just air as I counted how many turns out it was and was about 3.75 turns out so I assume thats just to adjust air. And from what I know the air/fuel mixture is suppose to be about a turn out and you go from there

Im aware that the miss probably doesnt have anything to do with the carb but im just covering the basics, my next focus would be looking at coils as the number 2 plug will get fouled which leads me to believe possible weak coil... I need to check them as the ignition wires are apart of the coils which I found odd

Anything else I should inspect and test?

 

[jerryjerry05]

The first three posts in the Force forum cover a LOT of things that can be checked.

Got a spark tester?
Any auto parts store they sell one that can measure the strength.
Spark should jump about 1/2"

The air screw is used for operation at idle.
​Once you get past 1100 rpm's it changes to the high speed jet.

The initial setting for the air screw is 1 1/2 turn out.
Needs to be set in the water, motor warm.
​3 1/2 is quite a way out?
​There is no high speed adjustment for the carb, just make sure the linkage is opening the carb all the way.
Rpm's at about 800 in gear. 1100 on the muffs.

​The #2 plug runs the fuel pump.
Take it apart and see if the diaphragm is damaged.
A fouling #2 could be that.
It also could be a crack block on the intake side(possible??).

​Any fuel/ mist coming out the carb as you run the motor? Reeds?

The coils: the wires are built in
They are also specific to the 50.
​The 85/90 etc. have shorter leads and might not fit.

​Pack and trigger: the trigger leads are very thin and break under the shrink wrap, the pack the connectors could be loose or need changing.
I change them ALL just in case??

 

[Gearboxz]

Yea I have a spark tester. I'll have to test spark strength of coils.

That is the only screw on the carb I could see, and yes it is set to 3-4 turns out and I didn't set it that way. That's why I asked so the screw in front of the carb opening right above it is suppose to be set to roughly 1.5 turns out.... ok Ill set it there and see what happens.

Fuel pump was rebuilt and Ill check it next time i take the boat to the lake to verify its still fouling it out.

No Mist coming out of the carb

I may just buy 2 new coils, since these are original to the boat. But 90 bucks a coil , so I may replace the #2 coil since that is the one that was fouling out originally.

Would the trigger cause intermittent misfire? It misses more so now since I changed the plugs from champion to NGK. But it runs gobs better... I know doesn't make sense but it does run better but now the miss is more pronounced. I have a set of champions in the glove box maybe ill throw those back in and see if changes that.

 

[jerryjerry05]

What plugs did you change to??
​Another poster was using plugs for an 85/125 not the recommended ones??

In over 30 years I have only seen 2 bad coils, so maybe yours aren't bad??

​The first 3 posts "stickys" have a lot of valuable info on making sure the motor runs right.
Read them.Carb setting is in there.

​The hard to remove brass plug: try using a piece of wire to see if the jet is open.
​A welders tip cleaner works great.
A can of carb cleaner in the jet after it's cleaned.

Trigger: the leads to the trigger are very thin.
​They can break and short out under the shrink wrap.
​Tug on each lead and see if it comes loose?

​outboardignitiondotcom has test procedures for your ignition system.

 

[Gearboxz]

I went from the champion to NGK BUHX. Does run better but misfire is more noticeable. I had champions UL18V

I did find the ground coming from the block to ground both coils was super loose. I tightened that down and haven't taken it to the lake yet to see if it cleared up the problem.

What brass plug those tiny ones on the outside of the carb?

I put the air screw where its suppose to be but wont be able to fine tune it until I get it in the lake. It seems to be running better, idle is higher now but I can turn it down once I'm able to run it in the lake and test it again.

Miss seems to be pronounced at high speed, but does do it at idle not very often but once in awhile... would a rectifier bother idle or would it be more so high speed?

SInce I did find that loose ground Ill have to test the boat on the water after setting idle and air screw first of course.

Idle should be in drive 750 - 800?

 

[Nordin]

Idle should be 750-800 RPM in gear in water.
Would be about 1100-1200 RPM in driveway if you using muffs.

 

[jerryjerry05]

Depending on the serial# UL18-V is for the newer motors?
L-82-C is for the older ????
​They use the same ignition just different plugs??

Your carb have a white plastic plug on the top of your carb?
Under that is the mid-range jet.