75 55 hp, Cover carb won't die

[FillupD]

I am working on my 55 hp 1975 motor and I am having trouble setting the carbs. The lower carb is nice and touchy and changes motor rpm and sound with just a little turn. The top carb adjustment screw can be ran all the way in or all the way out with no change. I tried a different needle and still no change. It is also belching fuel out the front, well not really belching but it is flooded.
When I put my hand over the throat, there is a vacuum to it but it doe not die like the lower one does. You put your hand on that one and the motor dies immediately. I have rebuilt, and cleaned these carbs more than once. I did not remove the bearing inside the air/fuel adjustment screw on the top of the carb though. Could a worn mixture screw or bearing cause this?
Any ideas what I can try. I am going to take it out to the lake tomorrow and see what it does on the water, at least it will start and stay running, albeit a little rough.
Thanks for any suggestions or opinions.

 

[tashasdaddy]

Re: 75 55 hp, Cover carb won't die

sounds like reed valves behind the carb, are bad. no a hard job to do. but check your compression on all cylinders.

 

[FillupD]

Re: 75 55 hp, Cover carb won't die

The compression is 130 and 135 PSI. so that sounds pretty good I would think.
If I replace valves, is it better to replace both sets or is it OK to have one new reed valve set an one old one?
I can't find the reed valves on iboats, just the gaskets. Is there a part number I can look for?

 

[tashasdaddy]

Re: 75 55 hp, Cover carb won't die

RETHOUGHT!!!!first i would be sure the float needle in the carb is not stuck. when you over the carb, it is like choking it, you should be flooding the motor with gas. you are not. could be that gas is not getting into the carb. pull the the bowl drain screw and see if any gas comes out. then pump the primer bulb and see if you can get gas.

 

[FillupD]

Re: 75 55 hp, Cover carb won't die

Ok, I'll give that a try and let you know what happens. There is gas on my hand when I cover it though. It will be easy to pull the drain plug so I'll do that first.
Thanks for your help

 

[FillupD]

Re: 75 55 hp, Cover carb won't die

There is fuel running out of the carburetor drain and when pumped.There is a little vacuum but it won't die like the bottom one does,(.5 seconds). This means I'm looking at the reed valves right?
I'm going to try to get it out in a bit and see what it acts like WOT.

 

[tashasdaddy]

Re: 75 55 hp, Cover carb won't die

i would not take it out, if it is not getting fuel, it is not getting oil. you do more damage. yes, sounds like reeds.

 

[FillupD]

Re: 75 55 hp, Cover carb won't die

Good Advice, I'll go the reed replacement route.

I can get a used reed block that would bolt in my motor. It states that they are in good condition. They are 40 bucks. I couldn't find any reeds on iboats. What can you expect to pay for reed replacement?

I guess my manual says to replace the reed as a set and its not worth the trouble of replacing individual reed valves in original block. It says to not turn them over and reuse a couple of times. This must have been a practice for awhile that didn't work out.

 

[FillupD]

Re: 75 55 hp, Cover carb won't die

Sorry, I'm looking for reed valves for a 1977, 55 hp motor.

 

[tashasdaddy]

Re: 75 55 hp, Cover carb won't die

1st there is not a 1975 55 hp what is your model #.
you can order them right here, also the gaskets will be needed http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f