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1985 30HP Carburetor Identification

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emilkob

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I just received a carburetor that is supposed to be for a 1985 30HP. What I received is tagged 393976. Every part diagram that I view says that the 1985 30HP carburetor is 393977 (very close). I assume this is a 30HP as the throat is the correct diameter, but I can not cross reference the 393976 part number anywhere. I called Evinrude, couldn't help. They sent me to a vintage dealer, couldn't help.

Anyone have any ideas what this is and why I cannot find it referenced anywhere?

IMG_3976.jpg
Thanks,

Emil
 
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Gotta be a 30, maybe supplied with a different jet size. It certainly should be referenced regardless of that. Maybe installed on a commercial model.
 
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Probably only one size richer on a commercial. I'm restoring a 1981 25 right now. I will head out to the shop to check jet size....I marked it down when I rebuilt the carb.IMG_20200815_092617596_compress59.jpg
 
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Here is the cowling. Decals are not available so had to just clear coat over them with epoxy after buffing them out. The 25 decal on back is hand drawn....all I could do. Ha! All models for 81 show a 59D main jet, however.
 

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Timguy, just had a chance to get back to the carburetor. I took out the oriface, and it is a 63D, same as listed in the diagram for the 393977 carburetor. I am at a loss why this is marked as a 393976 carburetor for which I cannot find any reference.

New question, I am trying to replace a 1988 30HP carburetor (0432021) with this 1985 carburetor. The 1988 30 HP carburetor has a 70D oriface.
The 1988 (432021) is listed as a successor of the 1985 carburetor (393977).

The 1985 and 1988 30HP engines share the same intake manifold part number.

Which oriface should I put in the 1985 carburetor when mounting to the 1988 engine?

Will putting the 1985 carburetor with the existing 63D on the 1988 engine cause it to run too lean?
Will putting the 1988 spec 70D orifice on the 1985 carburetor cause the 1988 engine to run too rich?
 
Right....gotta keep jet size with original carb it came with. That has always worked for me. Subtle differences in carb design will dictate the jet size for each application.
 
Thanks Timguy. It’ll be about a month before I get the car. On the motor and take it out for a test drive. I’ll let you know how it turns out.
 
OK Timguy, got the 30 HP carb on the boat. I actually did a conversion from 20 HP and also installed the 30 HP manifold. The boat definitely has more power and top end.

However, it is misfiring some at around 1900-2300 rpms. New sparkplugs.

Any suggestions on a troubleshooting process?
 
I'll do some checking for you. Gotta look around my mess here and check some parts. So what motor did you start out with? Better asked....what is the model number of your motor?
 
timguy said:
I'll do some checking for you. Gotta look around my mess here and check some parts. So what motor did you start out with? Better asked....what is the model number of your motor?
Click to expand...

The engine is a J20ECCA. 1988 20 HP

The carburetor is 393976 from a 1985 30HP. I don’t know the number of the manifold but am told it came from a 1985 as well. The manifold came with a reed plate, and so I replaced the reed plate that was on the engine with the one that came with the 30 HP manifold.

The engine starts right up, idles smoothly, runs great at high RPM, but has a periodic miss around 1800-2300 rpm. By periodic I mean a miss once every two seconds or so.

I say miss because it isn’t a backfire. It sounds/feels as if it bogs down but then comes right back.

I appreciate your thoughts! Thank you.
 
emilkob said:
The engine is a J20ECCA. 1988 20 HP

The carburetor is 393976 from a 1985 30HP. I don’t know the number of the manifold but am told it came from a 1985 as well. The manifold came with a reed plate, and so I replaced the reed plate that was on the engine with the one that came with the 30 HP manifold.

The engine starts right up, idles smoothly, runs great at high RPM, but has a periodic miss around 1800-2300 rpm. By periodic I mean a miss once every two seconds or so.

I say miss because it isn’t a backfire. It sounds/feels as if it bogs down but then comes right back.

I appreciate your thoughts! Thank you.
Click to expand...
I did the same conversion this spring accept it was an 1985 20hp with a carb and manifold from a 1988 30hp.Did not have any issues..Uses more gas for sure.Did you try link and sync again?May have to advance or retard cam roller for when butterfly opens.
 
Checked my motors around here and it looks like the cam on stator is the same as well as the exhaust tuners. As you might try what Yota suggested, adjust roller to cam relationship.
 
If the misfire is like a mild lean sneeze at about "No Wake Zone" speed, adjust the 'roller touches cam' point, to touch past the mark 1/4 to 3/8 inch. This is per a factory memo from the late 80's?

Worked for me on a 1980 25 hp with manifold, carb, primer, fuel pump/vacuum cover off a 1990 30 hp. I used the reeds from the 1990 with the '80 reed stops, because the reed stops are set wider. identical reeds. Runs like it should.

The carb jetting difference may be from running at different altitudes.
 
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