added fuel now it running like _______!!!

[Simple_Man]

1987 85 hp ran great the for the last month. I added fuel today, now it wont get passed 2500 rpm. Good spark all three, compression is 125 on all three. I checked the fuel pump, no tears. clear fuel filter is staying full. Any suggestions would be great.

 

[Jiggz]

If the clear fuel filter is staying full, it means fuel delivery is good. So the problem is with the carburetion. Since there are three carbs, the best diagnosis is to pull on plug wire one at a time while the engine is idling and listen for changes in engine rpm. Or you can do the spray bottle diagnosis but you will need to remove the carbs' air cover to do so.

Spray fuel oil mix directly into each carb while engine is idling. Any increase in rpm indicates that carb is not providing fuel to the motor. If the engine stalls when you spray into a carb, it means that carb is providing fuel and gets flooded or gets too rich and dies.

Now, don't assume it's all carburetion problem, because it can also be a reed problem. And the diagnosis for reed problem is to watch for carb blowback from each of the carbs. If there is too much carb blowback that is a sure indication of a bad reed.

 

[Simple_Man]

Thanks Jiggz can I do that test at idle at the dock. And how do I check the reeds?

 

[Jiggz]

You can even do the test at the driveway with muffs. And yes, of course you can also do it at the dock. To test for the reeds blowback, get a piece of cardboard 6"X6" or a little larger. While the engine is idling (with carb's air covers) removed, hold the cardboard about 4~6 inches away from the mouth of each carb. And then with other hand try revving the motor just a little bit.

You only need to hold it there for about 5~10 seconds. Take note of the blowback from each carb. 2-cycle engines always have a little blowback. Make comparison and the one with more wetting is most likely have a faulty reed. Ultimately, you will need to dismount the carb and the intake adapter to pull out the reed to do a visual inspection.

 

[Simple_Man]

I did the spray bottle test. top 2 carbs made it bog bottom carb no change. Also it is running a little smoother but i can't get over 3000rpm. I also checked for top dead center.

 

[Simple_Man]

No Title

I think I found the problem. The top carb is cracked. Haven't had them off in 2+ Yrs. I also checked the reeds, they are fine. Hopefully I can find a carb, and a gasket set. reasonably priced.

 

[Jiggz]

With a broken mounting ear hole, it sure will cause the engine to misfire due to the fact the carb is sucking air instead of fuel air mixture. Boat yard or the bidding store is probably the only place you can get a replacement one. Or may some super epoxy for last resort.

 

[Simple_Man]

Yeah it was weird yesterday started it up was running a lot better, as the morning went it ran good the bad then_____ then ok then ughhh. I will let you know how it goes.

Oh another ???? are all 3 carbs the same except for the inlets and throttle control, and can they be changed?

 

[SkiDad]

not sure if this matches or not: http://www.ebay.com/itm/Force-85-HP...ash=item1c8463f1a6:g:lngAAOSw7GRZC~-y&vxp=mtr

 

[Simple_Man]

Thanks SkiDad I found a full set just hope they are not corroded to ____ on the inside.

 

[Jiggz]

Yes all three carbs are identical except for the fuel connections depending on its location.

 

[Simple_Man]

Thanks

 

[jerryjerry05]

The one in the pic is the top carb.
​Trying to remove the inlet?? it's pressed in and trying to change it can destroy it.
​Good luck with the ones you got.

 

[Simple_Man]

Good to know. Thanks for that info.I have a full set coming. Thanks Jerry

 

[Simple_Man]

It's running again. Thanks Everybody:joyous:

 

[Jiggz]

Great.

 

[Simple_Man]

UGHHHHH ran great yesterday. took it out today died right off the dock when I gave it half throttle. re cleaned and checked the carbs. It will only start if I spray fuel mix into the carbs. but it dies right away.

 

[Jiggz]

Is the clear fuel filter still staying full? If yes, check the fuel air mixture screws make sure all are set to at least 1 ~ 1 1/4 turn out or even up to 1 1/2 turn out from seated. Check make sure all bowls are filling with fuel. Try the primer bulb to make sure it is firm.

If the clear fuel filter is empty, you could have fuel delivery problem.

 

[jerryjerry05]

When you cleaned the carbs did you use anything like WD or a silicone spray?
Those sprays can make the needle stick.
​I use Dawn detergent. I mix it in a spray bottle with water.
​Then I rinse with water and then blow dry.
Then install.

The floats adjusted right?

​Once the ball gets pumped up, loosen one of the bowls and see if the fuel drips out.

 

[Simple_Man]

I used dawn. Scrubbed with an old toothbrush, used a long needle to prob the long tube in the stem. let them soak overnight. then i scrubbed them again, rinsed and blew dry with compressed air. reassembled. Then I did a link and sync. It started right up. I ajusted my idle. Was running good. next day died, no restart. I will let everybody know what I find today..