Evinrude 9.9/15 throttle blocked from full opening.

[driver0606]

I have a 1989 9.9 Evinrude which has been recently fitted with a 15 hp carburetter.

There is a screw, part of the cam roller arm the operates the throttle, that fouls the casting of what appears to be the inlet manifold allowing less than half throttle. A photograph is attached, with an arrow showing where it fouls. I am unsure why this is. Any ideas, please?

 

[Chinewalker]

Are you saying it hits the carb body? Not sure how that's possible. The carb manifold is BEHIND the cam follower, so there's no way for the screw to hit that, either.

 

[oldboat1]

wow. how about a wider shot (no clue from that one, so far). will say this, if you have a sailmaster or yachtwin model there (looks like an elec start flywheel), it probably already had a 15 hp carb, at least a 15 hp carb body. Probably with the intermediate jet. You can tell by looking at the throat size -- some pics on Leroy's Ramblings, if curious.

 

[driver0606]

Thanks, guys, I will get some better photos next week.

 

[racerone]

Did the existing carburetor have a plastic cover ??---Does the replacement carburetor have a plastic cover ??

 

[oldboat1]

yeah, cam follower looks right for an '89 +/-, but would look for a black plastic cover. Doesn't look to me like the carb body with the cover removed, either. good mystery.

 

[Vic.S]

good mystery.

I hope you guys can solve it.

The OP originally asked the question on the UK's YBW forums.
I suggested that if anyone could answer the question he'd find them here on iboats.

 

[oldboat1]

Ha. cam follower adjustment screw has to be backed off counterclockwise. Follower link arm will rotate clockwise, changing adj screw angle and providing clearance for the screw.

(edit -- but think the pic is photoshopped....)

 

[driver0606]

Hello.
Thank you for all of your replies. Here is a wider view photo with the offending screw indicated with a black arrow. The screw is fitted in a white part that I believe is called the cam arm. In the photo the cam arm roller fitted to the cam arm is above and slightly to the left of the screw. At about 60 degrees of throttle the screw head fouls on a bulge in the top of the carb by the arrow. The black plastic two piece top has been removed for the photo. The screw seems to make a limited adjustment of the cam arm, which has a U shaped section, by opening the gap at the top of the U. I do not see its purpose. The cam arm rotates on a screw that goes into the carb body.

I could perhaps solve the problem by either-
1) Putting a distance piece or washers behind the white plastic cam arm, moving the arm away from the bulge and allowing full movement, but this would alter the relationship between the throttle opening and the ignition timing, presumably affecting performance. Maybe there should have been a distance piece.
2) Cutting the screw head off and making a screwdriver slot, but this does not explain why it is wrong.

As ever, your comments and explanation of how the cam arm is adjusted will be most appreciated.

 

[oldboat1]

nothing to fix, as I see it. IMO, the adj screw is turned in too far (clockwise). If backed out, the arm will swing back toward the carb, and the screw will no longer bind (will move back with the arm, and the head will tilt slightly upward.) Probably more important, the roller will be adjusted back where it should be at it's normal setting .

 

[Chinewalker]

There should be a thick washer at the base of the shoulder bolt that spaces the cam footer assembly away from the carb. It MUST be there. It is maybe a couple mm thick. OEM part number is 330190.

 

[racerone]

Wrong carburetor for an 89 model.

 

[oldboat1]

Wrong carburetor for an 89 model.

that's a good point ('89 would have plastic top, with a different gasket). Earlier model might be taller, and likely bind.

 

[driver0606]

Thanks. However, this carb, has a black plastic two piece air intake that I removed for the photo. Does that still make it wrong?

 

[racerone]

Yes, the 89 would have a plastic cover on top of the carburetor.--In addition to the 2 piece air silencer.---The carburetor on this motor now did not use a roller assembly with that screw.--Is that thick washer in place ?

 

[Chinewalker]

Carb style doesn't make a difference. The roller cam assembly is the same either way. Same cam roller assembly was used from the 1970s to the 1990s, traversing the transition from aluminum body carbs to plastic capped. The washer needs to be in there is is likely the cause of the issue.

 

[driver0606]

Definately no washer, but no free space on the securing bolt (which should have a shoulder) for it either. Maybe its the wrong bolt. I am awaiting the return of my original carb, which may make things clearer.

 

[racerone]

They all use that washer.-----Post a picture of the bolt !!

 

[Chinewalker]

Doesn't need to be any "free space" on the bolt. The washer goes between the shoulder and the carb. Unless someone has replaced your shoulder bolt with something else...

 

[thumbnut]

My '76 has no spacer and does not use the adjustable roller assy. On my '76 the cam itself is adjustable for pickup point with no adjustment for full throttle plate opening. Your motor uses the adjustable roller assy for pickup point with a jack screw on the cam for throttle plate max opening adjustment. My '76 has the larger roller instead of the small one so I had to make that cut corner on the choke spring plate for clearance. You have an early model carb body with no shoulder bolt spacer. Just use a Bic to heat the area of interference on the air box. When plastic is hot use something other than your finger to push in the affected area for clearance. Than set the pickup point and max throttle opening. Just a note...on mine if the plate over rotates and drops past the main nozzle just a little it runs real rich at that point.