'79 55hp Evenrude

[jwmullins79]

Ok, I'm new to the forum, and I'm sure this has been posted before, but I didn't wanna go threw 1000 pages of forums, and didn't see a search engine to do a search on it.

I have a '79 55hp Evenrude, and it runs good for me. Been doin all I want, but it doesn't seem to wanna idle while sittin in the water. Hooked to the flusher in the yard, it'll idle all day long. But put it in the water, and it won't idle correctly. If I just barely bump the idle lever, it'll idle fine. Can bump it minimally, enough that ya can't even hear a difference in the RPMs. I can't seem to get the carbs to let it idle right in the water. I've tried gettin them adjusted for hours on end, but can't get them just right. Any thoughts??

 

[F_R]

Re: '79 55hp Evenrude

Exactly what are you adjusting anyway? Those carbs have all fixed jets, no adjustment possible.

There is the adjustments to the throttle levers. Do you have that all sync'd?

 

[HighTrim]

Re: '79 55hp Evenrude

I believe he is referring to the fast idle lever.

The way it runs on the muffs is nothing like on the water when their is backpressure on the exhaust.

What is the idle on the water? Should be 650 Rpm in gear under load. ABOUT 1000 to 1100 on muffs.

 

[jwmullins79]

Re: '79 55hp Evenrude

I believe that it's the fuel/air mixture on the carbs that I've been adjusting. It's the brass screw ontop of each of the carbs that I've been adjusting.

Also had a question about the water pump on this thing. It's pumping out the exhaust ports on the back side of the unit while the boat is sittin in the water, but when I put it on the flushers at the house, it don't come out the flusher. It comes out the holes just above the fin, and it's warm, so it's gotta be makin it threw the engine. Should it come out the exhaust holes while on the water hose??

 

[jwmullins79]

Re: '79 55hp Evenrude

I believe he is referring to the fast idle lever.

The way it runs on the muffs is nothing like on the water when their is backpressure on the exhaust.

What is the idle on the water? Should be 650 Rpm in gear under load. ABOUT 1000 to 1100 on muffs.

It definatly runs higher on the RPM's on the hose than it does in the water. I know that this is normal. And yes I was referin to bumpin the throttle, I was referin to the fast idle lever. When bumping this it idles normally in the water. I don't have an RPM gun to check it's numbers when it's runnin. I know a little bout boats and engines, so not completely clueless. But not proficient with them either.

 

[F_R]

Re: '79 55hp Evenrude

I believe that it's the fuel/air mixture on the carbs that I've been adjusting. It's the brass screw ontop of each of the carbs that I've been adjusting.

Also had a question about the water pump on this thing. It's pumping out the exhaust ports on the back side of the unit while the boat is sittin in the water, but when I put it on the flushers at the house, it don't come out the flusher. It comes out the holes just above the fin, and it's warm, so it's gotta be makin it threw the engine. Should it come out the exhaust holes while on the water hose??

The screw that is looking right at you above the carburetor bore is a plug, not a mixture screw. It is supposed to have a gasket under the head and be screwed all the way in tight. If you are trying to adjust that, that explains why you can't get it right.

Back pressure on the exhaust when on a boat in the water is what makes the water blow out the relief holes in the back. No back pressure, no blow.

 

[HighTrim]

Re: '79 55hp Evenrude

#40 on the diagram? That is the fast idle lever. Is this what helps it run?

"http://www.crowleymarine.com/brp_parts/diagrams/31747.cfm"

 

[tashasdaddy]

Re: '79 55hp Evenrude

there is not an adjustment screw on that carb, i believe you have been turning # 30 in the diagram, which has a washer on to seal the low speed fixed jet. clik on diagram to enlarge.

 

[tashasdaddy]

Re: '79 55hp Evenrude

idle speed adjustment screw is # 51 in this diagram, this controls the idle speed.

 

[HighTrim]

Re: '79 55hp Evenrude

ttt

 

[jwmullins79]

Re: '79 55hp Evenrude

there is not an adjustment screw on that carb, i believe you have been turning # 30 in the diagram, which has a washer on to seal the low speed fixed jet. clik on diagram to enlarge.

Yes, this is what I have been tweeking, and it has been effecting the way it runs. Got it runnin the best it will from messin with them. How should these be adjusted??

 

[jwmullins79]

Re: '79 55hp Evenrude

idle speed adjustment screw is # 51 in this diagram, this controls the idle speed.

I'll adjust this the next time I get it set in the water. See if I can get it right with this. Thanks for the help ya'll. And sorry it took a little while for me to get back, my fiance's truck wouldn't start, so had to go to town and jump it off so that she could get home.

 

[F_R]

Re: '79 55hp Evenrude

Yes, this is what I have been tweeking, and it has been effecting the way it runs. Got it runnin the best it will from messin with them. How should these be adjusted??

Sure, that will affect the way it runs. They are supposed to be screwed firmly all the way in. Then the fixed jet behind it can do it's job. Otherwise, with them loose you are sucking air past the threads, upsetting the air/fuel ratio.

After you screw them in like they are supposed to be, then adjust the idle speed (RPM) with the other adjustment screw that tash posted.