Carb Problems?

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Hello everyone, one quick question, I have an 85 force that is giving me fits. I took her out today and tried to idle adjust no 1 carb, I could screw adjustment screw all the way in, and the motor idled up but never shut down. My question is it time to rebuild card, or at leat vat it and blow air through it? No. 2 and 3 worked well, very senstive to any movment of the idle jet. Thanks, D.W.H
 

tater76

Senior Chief Petty Officer
Joined
May 7, 2010
Messages
712
Re: Carb Problems?

Your idle adjustment is not on the carbs. The screw you turned is the mixture screw, it should be set at 1 to 1 1/4 turns out from lightly seated. You need to refer to the link and sync sticky in the FAQ section of this forum. It needs to be done, and will help familiarize you with the procedure.
The idle is set on the side of the motor, its called the timing tower. It is the rod that runs vertical from the base plate to the flywheel. About a quarter to halfway up from the bottom of the tower is an adjustment screw that controls the idle. Everything else you need to know will be in the sticky.
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Carb Problems?

Been there done that tater, I just mis-spoke. If the mixture screw is shut down the motor should die, should it not? After four months of tinkering I've become quite familiar with link and sync, and idle adjustments. I've had the powerhead off last week to replace a powerhead/adapter head gasket, which went well, motor fired right back up after re-assembly. Thanks D.W.H.
 

foodfisher

Captain
Joined
Feb 18, 2009
Messages
3,756
Re: Carb Problems?

. If the mixture screw is shut down the motor should die, should it not?

You've still got two cylinders to keep the engine running, although with less power and doing possible damage to the nonresponsive cylinder. Suggest a compression test on the top cylinder and/or a thurough cleaning of the carb.
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Carb Problems?

Thanks, carb is soaking in carb cleaner overnight. I've checked compression not recently however. The last time I checked three weeks ago it was around 115. I'll recheck tommorrow.
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,817
Re: Carb Problems?

Been there done that tater, I just mis-spoke. If the mixture screw is shut down the motor should die, should it not? After four months of tinkering I've become quite familiar with link and sync, and idle adjustments. I've had the powerhead off last week to replace a powerhead/adapter head gasket, which went well, motor fired right back up after re-assembly. Thanks D.W.H.

If it's a single carb engine, yes the engine could die assuming the idle screw is not screwed all the way in that the carb is actually running on the idle jet and not off the main jet. However, if the idle screw is set properly (1100-1200 RPM on muffs and neutral) you should notice a change in engine rpm when you decided to screw in all the way the idle mixture screw (air screw).

If you did not notice any change in rpm, then it tells you the idle port could be blocked. Remove the air screw and check the needle point. Make sure it is still in perfect needle shape. If it's bent or blunt on the tip, replace it. Use carb cleaner or break cleaner and shoot the port. Sometimes I just use low pressure air and then re-install the needle all the way.

Be careful and do it slowly just before hitting bottom to avoid damaging the tip and also the port. And then do the synch and link as you have mentioned you are familiar with already.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: Carb Problems?

Compression on 1 /115 or all 3 at 115??
Get another guage and see what it reads.
You pulling all plugs when doing the test?
 

Aggitated

Seaman
Joined
Apr 18, 2012
Messages
61
Re: Carb Problems?

All three around 115 - 120. Another guage showed 145 on all three. I didn't do the test but I belive it is reliable 9 I put in boat in shop a couple of months ago, and the mechanic did that particuliar test) Yep. pulling all plugs and checking at WOT. Going through the carbs now, waiting on parts. One carb was missing a float bowl spring..hum.... Float level on two of them looked low according to the book. I'll reset and wait on parts. Was loooking into ultra-sound cleaning for carbs, but at 85 bucks a carb, no can do. She sits for the next few days. Thanks JerryJerry.
 
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