1985 Evinrude Fuel Mixture Screw

[chrisflyfishes]

Just acquired a 1985 Evinrude 115 V4 (E115TLCO) here in Denver. My understanding from the seller is that he got it from a guy that owned it down in Texas. The motor runs pretty rough, and the seller gave me the impression that he never did more than put gas in it and pull his kids around. So I'm pretty confident that the air/fuel mix into the carb is way off. I'm looking around the motor and what I *believe* is the fuel mixture screw is actually a T-post looking thing on the port side of the engine (opposite side from the throttle assembly and idle adjustment screw).

Anybody out there with experience on this motor that can confirm that? If so, it looks like you need a special notched tool to turn those (or use some needle nose pliers, I guess).

Anybody have a wild guess as to how many turns back from zero would be a good place to start adjusting for 5,000ft?

 

[racerone]

There are no mixture adjusting screws on these carburetors !!

 

[chrisflyfishes]

There are no mixture adjusting screws on these carburetors !!

Whaaa? Seriously?

I'm reading then manual for this engine. It specifically has a section for Carb Mixture Adjustments on page 1-65. First step:

1. Temporarily iпstаll kпоЬs оп low-speed апd high-speed пееdlеs .

I assume these are the adjustment "screws" to adjust fuel/air. No? Then how is the air/fuel adjustment made for lean/rich?


Thanks!

 

[flyingscott]

I don't think that is for your motor. Your motor has a fixed high speed jet and low speed orifice. First I would do a compression test then find the altitude chart for your motor. Then you can replace those with the correct ones.

 

[racerone]

I guess I have to repeat here.-----There are no mixture adjustment screws on a 1985 model 115 HP Evinrude !!----You need to find the correct manual !!

 

[chrisflyfishes]

I guess I have to repeat here.-----There are no mixture adjustment screws on a 1985 model 115 HP Evinrude !!----You need to find the correct manual !!

Thanks to both flyingscott and racerone. The manual below is the one that I am referencing. It clearly marks my motor (E115TLCO). If this isn't the correct manual, then perhaps you can point me to the correct one. But I think this is a matter of me (a) making assumptions about this carbureted motor, and (b) misinterpreting the manual.

I searched the PDF manual for the word "altitude". 9 mentions in the manual. #1 mention is in the table of contents: Weather, Altitude and Engine Performance.....1-63.

Now we're getting somewhere. Reviewing that page, it does say that engines running at high altitude should install a high altitude kit (P/ N 393533). I did a google search for that exact part number and couldn't find one. Crowley Marine has a high altitude kit, but I'm not convinced it's the correct part. I have a local dealer here that I'm going to take the motor to for a complete tune-up, and I'll be sure to ask that this kit is part of the tune-up. I just wanted to do a little to increase the performance before all of our lakes close in a couple of weeks.

Having said all that (and again, thank you both for pointing me in the right direction), then what is the manual talking about with respect to Carburetor Mixture Adjustment? I assumed it was talking about the screws that most carburetors have that allow the air/fuel ratio to be adjusted (which is what led to this post in the first place). Is this an adjustment that the average guy can/should do?

 

[racerone]

Can you not see that the page in the manual is for the 2 HP model and the bottom part of the page is for 4 to 15 HP models.----You need to reduce orifice size for the 4 high speed jets by 0.002".-----But first post your compression numbers on this 35 year old crossflow motor.----I am sure your local dealer is well aware of what to do for 5000' elevation operation.

 

[racerone]

Get the authorized local dealer to print out service bulletins with regard to jetting for high elevation running.----Dealer did that for me.

 

[chrisflyfishes]

Can you not see that the page in the manual is for the 2 HP model and the bottom part of the page is for 4 to 15 HP models.----You need to reduce orifice size for the 4 high speed jets by 0.002".-----But first post your compression numbers on this 35 year old crossflow motor.----I am sure your local dealer is well aware of what to do for 5000' elevation operation.

LOL. Actually - no. I cannot. And I still don't.

I tested the compression when I bought the boat from the guy and the exact number escapes me, but it was around 105-106ish and they were all the same.

I've got this motor scheduled at my local shop and, like you say, I'm sure they deal with this on a fairly regular basis. So when they do the complete tune up, we'll certainly address this high altitude issue.

But what I DO see is a regular Joe that remembers what it was like to work with carburetors 45 years ago when a regular Joe could still do that kind of stuff. My 2019 Merc Pro XS has all kinds of computers so that the EFI auto compensates for stuff like that. Same thing goes for my 2014 SuperDuty. If it wasn't for YouTube and forums, I'd be right there with every chick that ever walked into a garage and let the service advisor sell her every stinking thing she doesn't really need.

So I got on this forum hoping to learn something. And I have. And I've thanked you a couple of times. But frankly, Racerone - you've managed to be helpful and condescending all at the same time. Talking to me like I should know all this BS and what kind of dumb@@@ even asks these kinds of questions. I probably shouldn't even own the stupid boat if I didn't know these things, right? If I knew these kinds of things, I wouldn't be on this forum in the first place, would I?

So just relax a tad, crack a beer and feel good about the fact that you taught me something that I didn't know.

Regards,

 

[racerone]

You need to read that page on carburetor adjustment carefully.----Slowly and word for word.------At the very top it indicates that it is for the 2 ( 2 hp ) model with a low and high speed mixture needle.----Then near the bottom it switches for the 4 to 15 ( 4 hp to 15 hp ) models that just have a low speed mixture needle !!-----The opportunity is there to learn mate.-----Read and heed.