95 Force 90HP Carb Adjust Problems

[walk-on]

Hello all. I've been reading this forum for quite some time and finally decided to join after getting some good info on tachs and props. I had fuel leaking from the top carb due to a bad cork gasket. I removed all the carbs to gain access and I tore the top (leaking) carb down as far as I could with the help of my Seloc manual. I backed the idle screw one full turn and the motor started right up and ran well. I wanted to adjust the idle mixture on all three carbs so I made the adjustments but I noticed no change in the motor when adjusting the second carb. I also could not drop the rpms (1100) at idle because I could not turn the main idle screw due to the nut that sets it tight. Anyway when I ran the motor it ran well until I dropped to half throttle. At that point the motor stalled. When I attempted to restart the motor it turned over slowly like the battery was almost dead. I increased the throttle and it started up and ran until I backed off to half throttle. I then adjusted each carb to one full turn from closed and that solved the stall at half throttle problem. The motor still turns over very hard when starting, but it runs well at WOT. It also seems to bog down a little when punching it from a standstill. What could be causing this? Are the problems related? It ran fine until I messed with it. That'll teach me! At least it doesn't leak fuel anymore. Thanks for your help.

 

[eurolarva]

Re: 95 Force 90HP Carb Adjust Problems

When engine stumbles or hesitates it means it is too rich. The idle screws need to go clockwise a bit. On the carburator you will notice where the mixture adjust screw goes into the carb. At the very end of the screw it is pointed and you will notice a welsh plug near where the screw ends. If you were to remove this welsh plug you would see three tiny holes. My guess is in your number 2 carb one or more of these holes has gum, varnish or crud in them. If it is a pain to take that carb off I would back off the mixture screw and remove it. Then take a carb cleaner or a contact cleaner (I like contact cleaner because it is not as harsh as carb cleaner) with the tube hooked up and spray some with the tube all the way into the mixture screw hole. Reinstall the mixture screw and back it off about 1 full turn and try it again and see if you can get it to work. The best way to get this crud out of them holes is to remove the carb and the welsh plug and clean the holes out with a wire and some carb cleaner, however the easy way may work if you are lucky.

 

[walk-on]

Re: 95 Force 90HP Carb Adjust Problems

Thanks for the advice eurolarva. I was just out in my driveway and checked on the mixture screws. The mixture screw on my number one carb was actually backed out almost two turns instead of one full turn like I thought it was. When I turned in the mixture screw on the top carb it kind of bound up a bit before going all the way in. So I was actually running with top carb almost two full turns out and other two carbs at one full turn out. Because of this, I think I'll just rebuild the carbs and be done with that part of it.

As for turning over hard, I checked the voltage on the battery and it is at 12.4 volts. Could a carb problem cause the motor to turn over slow or is it just a coincidence that this problem showed up right after I adjusted the idle mixture screws? Thanks!

 

[Reel-Fun]

Re: 95 Force 90HP Carb Adjust Problems

if voltage does'nt drop to much while starting and running then id say you may have a weak starter.

 

[walk-on]

Re: 95 Force 90HP Carb Adjust Problems

I've turned into a madman. I went into the boat yesterday and checked the voltage of the battery and tightened the cables on the battery a bit tighter than they were. I have a set of muffs that I don't like to use because the water doesn't come out of the pee hole unless I rev the engine. I hadn't had the impeller changed in the two years that I have owned this used boat so I bought the parts, dropped the lower unit and changed the impeller and gaskets. Still didn't spit water from pee hole but it works great in the bucket. I'm still waiting for my carb kits to come in, but the motor starts right up and idles between 800 and 900 (spec is 700 to 800). I'm going to wait until I rebuild the carbs before I mess with it again. I'll check the voltage next time I start it up. Thanks for all of your help.