Main Fuel Jets

[scb82901]

I relocated a 1984 85 hp force, model 856X4L from Wyoming, elevation 6000 ft., to Florida, elevation 0 ft. I'm looking for main fuel jets to use at sea level. My manual says they are .072. These are for the Walbro carburetors, model WE-4-1 and/or WE-4-2. Any help locating these is greatly appreciated.

 

[kbh121956]

scb82901, Marine engine dot com has your needed jets. Also franz marine dot com might have them.

 

[scb82901]

Thanks,
I'll check them out.

 

[jerryjerry05]

Have you looked at your jets?
You might not need anything???
F10173 is the part# for the jet. you need
There is one (1) on e-bay

 

[scb82901]

I took the bottom out to see what it looked like. It appears in good shape. The motor runs, but coughs every couple of seconds. My theory is that it's running lean with the high altitude jets not allowing enough gas for the low altitude air.

 

[jimmbo]

If it is coughing at idle and low speed, changing the main jet will have no effect. Sounds like it needs an adjustment of the idle mixture

 

[scb82901]

No, the coughing is at high rpm, which is why I think it's the main fuel jets. The idle mixture seems fine.

 

[fishrdan]

Don't run the outboard under load until you have determined it has the correct low altitude (stock) jets or you could melt a piston.

If the boat lived at 6000' in Wyoming, I would suspect it has high altitude jets.

 

[jerryjerry05]

You need to take the carbs apart and see what's in there?
They have the size marked on the jet.

Your motor is 30+ years old.
You sure it was bought and sold in the west?

High speed cough: could be it's sucking air somewhere??

Get it running and spray starting fluid around the base of the carbs and the intake side(port covers, fuel pump) of the motor.
If it makes any difference in the way it runs?? then it's sucking air.

ONE!!!!! little cough, backfire, or stutter can blow the port cover gaskets.

Try this: get the motor up to operating temp.
The run it at high speed and then shut the motor off.
Don't bring the throttle back or shift to N just turn the key off.
Then pull the plugs and check the condition.
Post pics.

 

[scb82901]

Thanks for the input. I am the original owner, and know for certain it has high altitude jets. I'll give these suggestions a try. I've also ordered a fuel pump rebuild kit, and am considering drilling out the high altitude jets to a larger diameter if I can't find the replacements. Any thoughts on that approach?

 

[Nordin]

2500-5000ft calls for .072 main jet, 5000-7500ft calls for .070 and sea level 0-2500ft for .074.

Do not try to drill it out your self, it is .002 in differens, really hard to do your self.


Try Franz Marine, he will have if they are still available and there is no money. I think about 10-15 dollars each.

 

[jerryjerry05]

E-bay for carbs
They sell complete sets fairly reasonable.
Or I should say some people sell them fairly reasonable(I did)
They have a bunch.

 

[scb82901]

Here are pictures of the plugs before and after the test described by jerryjerry05 in post #9.

 

[jerryjerry05]

How long did you run it at wide open?
They sure don't look like they're running hot.

Still wondering what jets you have?
Just because you bought it in the mountains doesn't mean they sold you a motor set up for there??

 

[scb82901]

I ran it at wide open for at least ten minutes.

Before I did any work on the jets, I rebuilt the fuel pump, as the original diaphragm was still installed. It made a difference, but did not fully solve the problem.

I talked to Franz Marine on the phone. They didn't have any of the jets I needed, but could have them made. I decided to modify mine before I went that route. Thanks to Franz Marine for their prompt response to my inquiry, though.

I bought some drill bits online, both #50 (.070) and #49 (.073). My original thought was to lock the jet in my Workmate, and drill the orifice out, but I wasn't sure I could control the process. I ended up locking the bit in the Workmate, and slowly reaming the orifice out by hand. It worked out pretty well. I reamed to .070 first, then went to .073.

After re-assembling everything, I fired it up and ran it for a while. After a few minutes, it seemed to smooth out. I also adjusted the idle needles, so it idles much better, at least on the hose. I'll get it in the water sometime next week and give it a workout.

Pictures of the jets and reaming process attached.

 

[jerryjerry05]

Keep us posted on how it runs?
I believe the procedure for setting the air screws in the water is in one of the top posts.
If not? ask and I'll post it.