1989 125HP Force Idle tube question?

Manual states that the idle tube in the carbs (must contact the front of the main nozzle).

The idle tubes on my 1989 125 Force are center of the nozzle. The caruretors are original since new and have never been rebuilt.

Manual states that if contact is not made with the nozzle the carburetors will operate excesively lean.


I also recently purchased a set of used carbs and the idle tubes are center of the nozzle also.

Could time and use have changed the position of the idle tubes in the nozzle?
Is this something I should be conerned about? Thanks!

Re: 1989 125HP Force Idle tube question?

My Seloc Man mentions nothing about it I can find. Only thing I spotted was the carbs are jetted differently, top and bottom...have to read about that a little further...didn't know that

Re: 1989 125HP Force Idle tube question?

Clymer Force outboard shop manual manual 4-150 Hp ( includes L-Drives) 1984-1999 Page 212.

Re: 1989 125HP Force Idle tube question?

Clymers T/P my book...like said, Seloc says zip about it. Keep in mind though, if flipping carbs, check the jet size.
Ya got "E" carbs according to my book.
That said, my take is is anything up/down must be seated, not sideways. Send PM to Frank A...he knows those motors well...

Re: 1989 125HP Force Idle tube question?

Reading into it a bit, (in my 1988 manual) the idle tube must contact the front of the main nozzle at the bottom of the idle tube. This will have the idle tube centered to slightly forward inside the main nozzle AT THE NOZZLE OPENING INSIDE THE VENTURI. This position puts the bulk of the main nozzle opening within the venturi negative pressure zone and allows for full circumference fuel draw. If the idle tube is rearward to resting against the rear surface of the main nozzle, it will partially blind the nozzle and cause weaker fuel draw--thus running a bit lean. Poor design, but it works. Actually, not poor design, rather a design within the constraints of price--simple cheap carb for an entry level priced engine. ----Now, if you could find some Dellorto's that fit-----

Older Chryslers and Forces had equal jets on both carbs and since the manifolds, pistons, and crankshaft cheeks are the same, I can only assume that in some way the top and bottom carbs are vented differently--perhaps to account for unburned fuel and oil recirculation through the reed plate orifices. Either that or the engineers found out that the balance tube between manifolds causes the top carb to run slightly leaner--thus the larger jet in an effort to have the engine run more efficiently. (Since at full throttle, air --oxygen-- is always the limited factor in an engine, less power is lost by having slight excess fuel, ensuring all the oxygen is burned, than by having a slight lean condition.) Older 140s had .096 jets in both carbs and I think the 125s had .093.

Just for s**ts and giggles, the 5 cylinder 150 (3.3125 bore) had the top and bottom carbs jetted equally and the center carb jetted way leaner---.093 top, .076 center.

Re: 1989 125HP Force Idle tube question?

Here's a picture Frank! What they call the front looks like the back to me! The blurred out wording at right bottom reads: (idle tube must contact nozzle here).

Can I bend them without having to take them out or is the only way to change the position to take them out? Or should I just leave them alone?
Thanks!

Re: 1989 125HP Force Idle tube question?

Danged if it doesn't look like the rear to me, too! My factory manual shows it in the forward position.

As far as position, if you haven't been having powerhead problems, leave them be. Don't mess with success.

Re: 1989 125HP Force Idle tube question?

Power head problems!

Compression
#1 140
#2 150
#3 145
#4 135

Re: 1989 125HP Force Idle tube question?

Driving me nuts here, but think I figured it out. That pic is either wrong, or during printing it was flipped (but looking again, that don't make sense either). If the idle tube should touch the front (Franks info makes sense to me) of the jet, it will be opposite (facing to the front, of where the Welsh plug is.
That pic shows it facing the rear of the carb, but the the rest of the carb diagram looks OK..showing it from the Port side. The top lug at the left is the plastic carb shield lug

Re: 1989 125HP Force Idle tube question?

I dug through my spare carbs last night, out of the five I have one has the idle tube touching the front of the nozzle opposite what the picture shows. The originals and the spare set I have are more or less in the center!
It's driving me nuts too!
Maybe there was some veriation from that rule from year to year or model!

Re: 1989 125HP Force Idle tube question?

I'd go ahead and bend'em a touch toward the front. What Frank said (and what said in the Manuals so far) makes sense to me. Rather more gas than less...right?

Re: 1989 125HP Force Idle tube question?

Tried bending them while installed, they spring right back!