1955 Evinrude 3 HP Air Silencer Problem

[exfoxpointer]

I have a '55 'Rude 3HP. I have rebuilt the carb (packings and boss gasket, other gaskets). In the process, I have cleaned and aired the needles and passages. I fired it up without the Air Silencer attached. Got my low speed idle set and high speed needle set for wot. It seems to be fine, until I put the silencer back on. Once I reattach it I can't find idle and forget about wot. I can hold a rag on the end of the silencer and get some better RPM's on both slow idle and wot but nothing like what I get when I take it completley off. They put that there for a reason, what am I missing?

 

[F_R]

Re: 1955 Evinrude 3 HP Air Silencer Problem

I have a '55 'Rude 3HP. I have rebuilt the carb (packings and boss gasket, other gaskets). In the process, I have cleaned and aired the needles and passages. I fired it up without the Air Silencer attached. Got my low speed idle set and high speed needle set for wot. It seems to be fine, until I put the silencer back on. Once I reattach it I can't find idle and forget about wot. I can hold a rag on the end of the silencer and get some better RPM's on both slow idle and wot but nothing like what I get when I take it completley off. They put that there for a reason, what am I missing?

Do you have the screen that goes between the silencer and carburetor? That is part of the system.

 

[exfoxpointer]

Re: 1955 Evinrude 3 HP Air Silencer Problem

Do you have the screen that goes between the silencer and carburetor? That is part of the system.

Yes, the screen is clean and it is in. I did take the silencer apart and found nothing inside impedeing the air flow. I will say that while it is off and the motor is running the carb seems a little "juicy". I am thinking that when I put the silencer back on, the carb might be flooding.

 

[exfoxpointer]

Re: 1955 Evinrude 3 HP Air Silencer Problem

Not sure if I posted my reply to your question correctly, so I am answering again...The screen is in, and it is clean. I did notice that while the motor is running and I have the silencer is not attached, there was a little bit of fuel dribbling out of the carb.....

 

[OLDIRON]

Re: 1955 Evinrude 3 HP Air Silencer Problem

My bet is the carb. You have a fuel delivery problem. These little guys are almost bullet proof.But they are a very low compression motor. If the fuel/air mix isn't good, they won't run good.Go through your carb again. On these older models I would go with an oem kit, new float, the works. Best of luck.

 

[exfoxpointer]

Re: 1955 Evinrude 3 HP Air Silencer Problem

My bet is the carb. You have a fuel delivery problem. These little guys are almost bullet proof.But they are a very low compression motor. If the fuel/air mix isn't good, they won't run good.Go through your carb again. On these older models I would go with an oem kit, new float, the works. Best of luck.

I bought the carb kit thru NAPA. I was thinking about getting another one and doing it again. I have never messed w/ an OB before this. Honestly, I forgot to put the packings in the needles the first time around, took it apart, realized the mistake and installed. That's when I got it to fire up and actually run. So much on his site talks about the BOSS gasket, which I guessed was the thicker white gasket in the kit, but pictures on this and other sites make it look like a cork type gasket. I fits perfectly where the hi-speed needle goes in so I am assuming this is correct.(no nomeclature) Do you know if it hurts to run w/o the silencer?

 

[Chinewalker]

Re: 1955 Evinrude 3 HP Air Silencer Problem

Those 3hp models are made to run with the silencer in place. The screen, in particular, is fairly important. As noted above, the low compression nature of these motors leads to poor fuel draw. With that in mind, the screen and air horn essentially make the motor run with a partial choke on at all times to help with fuel draw. Running without the horn can actually lead to a lean condition.

The thick cork gasket goes inside the carburetor, between the standpipe in the carb bowl and the down tube from the carb body. Motor will run poorly if that is not installed.

 

[exfoxpointer]

Re: 1955 Evinrude 3 HP Air Silencer Problem

Those 3hp models are made to run with the silencer in place. The screen, in particular, is fairly important. As noted above, the low compression nature of these motors leads to poor fuel draw. With that in mind, the screen and air horn essentially make the motor run with a partial choke on at all times to help with fuel draw. Running without the horn can actually lead to a lean condition.

The thick cork gasket goes inside the carburetor, between the standpipe in the carb bowl and the down tube from the carb body. Motor will run poorly if that is not installed.

Maybe they sold me the wrong kit, it did not have a thick cork gasket. The one I used was the most different from all the rest and definitely thicker. It was sort of a plastic like gasket, cream colored. I put that in the spot, it didn't hug the high speed nozzle too tightly, kinda snug. I did have a small gap between he two halves of the carb that closed up when I tightened the screws. I haven't ordered the new kit (again) yet..been busy with work and wife. Does the material make that big of deal? Should the high speed nozzle slip right through, or should I have to "screw" it in?

 

[tx1961whaler]

Re: 1955 Evinrude 3 HP Air Silencer Problem

That gasket is rubbery plastic in the new kits. It fits on there pretty tightly.

 

[Chinewalker]

Re: 1955 Evinrude 3 HP Air Silencer Problem

The new kits do have a rubbery flat o-ring in place of the old cork one. Should be fine. The high speed nozzle is threaded into the carb body - make sure it's seated properly.