1998 Force 90 carb issues, lower needle valve sticking.

[Onthecoast]

I've got a 98 Force 90 on the back of a 70's Wellcraft 17V Fisherman. It ran pretty good last year, but was in need of some carb work at that time. Come this year, it would run at all even though it was drained of fuel last year. I pulled the carbs and they were a mess, cleaned them out really well and thought that would have it licked. Hooked everything up and it still won't run. It will run when you spray starting fluid into the chamber which tells me that my spark must be decent enough but that I am still having a fuel issue. One thing I did notice is that one of the lower needle valves did not move freely. This is my first experience with carburators that have lower needle valves that aren't attached to the float. I'm guessing that in order to work properly, the needles need to be able to move pretty freely up and down within the restriction of only going as high as the seat and as low as the float will allow. I do not believe that the seat is serviceable so what do I need to do here. In actuality, the carbs need to be taken down again and rebuilt with new gaskets, so I should probably go ahead and do that, but can someone help me out with the needle valve question?

 

[jerryjerry05]

Re: 1998 Force 90 carb issues, lower needle valve sticking.

First thing do a compression test.
The needle should move freely.
Don't use anything other than a carb cleaner(on realllllly crusty carbs) or Dawn dish soap.
If they are really bad a spray cleaner will help.
Usually Dawn works.I use soap/water and then use compressed air to dry.
I don't use any sprays like WD or any silicone sprays.
Ethanol is messing up the carbs and the rubber in the needle/seats.
Where you located? Profile.
You might be close to someone who can help.
Air screws should be set at 1 turn out for inital settings.

 

[Onthecoast]

Re: 1998 Force 90 carb issues, lower needle valve sticking.

Carbs are good and clean but the needle valves are sticking. I'm going to order some new ones and a set of gaskets for each carb. I can get it running but I'm having some misses and it is hard to start. I can get it running with starting fluid so I'm thinking that rules out airflow and or spark. I went ahead and replaced the plugs, but it didn't help much. I can get it to idle, but it has a noticeable miss and when I up the RPM's the miss is more pronounced. I'm guessing it is due to a fuel issue in one of the carbs, most likely from the sticking needle valve. i'm going to replace those and see where it gets me. If that doesn't do it I'm not sure where to go next.

Compression was recently tested by my father and was within spec. I'm located on the Mississippi Gulf Coast.

 

[jerryjerry05]

Re: 1998 Force 90 carb issues, lower needle valve sticking.

Do another test,post the #s and check the plugs for even burn.
Check the fuel pump diaphragm.
Then check for water in the fuel?

 

[Onthecoast]

Re: 1998 Force 90 carb issues, lower needle valve sticking.

Compression test might be a little while due to not having the tools myself. Fuel is good, just mixed up a fresh batch. I seem to be getting good fresh fuel to the carb, what's going on inside in all three, I'm not sure about. See through fuel filter looks good and full but I haven't checked the actual diaphragm. If it was bad, wouldn't the fuel level in the filter be dropping?

 

[jerryjerry05]

Re: 1998 Force 90 carb issues, lower needle valve sticking.

Not necessarily.
It's easy to check.

 

[barca239]

I have a similar problem, the inlet needle valve on my merc didnt move freely and would not let fuel enter into the float chamber.
I removed the carb and cleaned it and used a small diameter wire that was flexible and went through all the opening to see remove any other possible particles and then blasted it with carb cleaner. i then proceeded to assemble it and when i did i tested if flow was restricted as i blew air into the fuel port ( where the fuel enteres the carb) the carb must be right side up and should feel some restriction but air should flow. If there is total resistance then the needle valve is is sticking especially if it has a rubber tip!!! Jsut buy a new inlet needle valve and that should fix It!!!

 

[MickLovin]

Check on your needle for wear, it is an easy enough job to replace both needle and seat, make sure your float levels are correct. If it is missing it could be starving for fuel on a particular cylinder, when you have it running take one plug out at a time and see if there is a difference. Probably just as easy to have your carbies soaked in cleaner and then blown out with compressed air in all orifices, but by trying to have it running and taking a plug out you may prove which particular cylinder/carbie it is. Make sure your fuel pump diaphragm is good, you will need new gaskets for this job and probably a new diaphragm. As mentioned previously, ethanol can play havoc with these old carbies.