1989 20hp Evenrude won't idle

[mbSandflea]

Finally took out the new to us boat today and after getting it started it moved around and ran fine. Whaler type skiff, 13ft with 20hp Evinrude that has a 35hp carb on it. Motor ran great at speed and hit 26mph on the GPS at WOT. The only problem was that it would only sit at idle with the choke lever pulled up. After pushing down the choke lever it's either shift into gear fast or the motor bogs down. It will restart with the choke lever up but does the same thing. This was AFTER running it approximately 12 to 15 miles. Any ideas or info is greatly appreciated, thanks.

 

[JB]

Re: 1989 20hp Evenrude won't idle

Well, you have run into the downside of "hopping up" outboards. The venturi in the 35hp carb is too big to provide a good mixture at idle air flow.<br /><br />You might get it to idle by going to a larger idle jet. That might bring up different problems.<br /><br />My advice is to go back to a 20hp carb or learn to live with choking it to get it to idle.

 

[mbSandflea]

Re: 1989 20hp Evenrude won't idle

It was bought this way, I didn't do it. Thanks for the info though, it's what I was looking for. Now I know to expect the problem and can adapt to it rather than wonder if it's something that can be changed by a tune up or that something is going wrong with the motor.

 

[G DANE]

Re: 1989 20hp Evenrude won't idle

I've found that the 20 HP runs fine with the 35 HP carbs, since the block is all the same. As the exhaust pipe is different, WOT wil not be the same. Clean and rebuild carb, and get hold of a manual, and readjust sync'n linck. ( Or search and find advice on how to do here. I ts all on this forum. Do a search here for iddle mixture adjustment and follow Joe Reeves excellent procedure. I'm sure you can get it to iddle fine, I did with quite a few. Sorry to differ from you otherwise always excellent advise JB, this was just my experience, I even build a 35, by using block from a 20, Head , carb, manifold and rest from a 35.

 

[JB]

Re: 1989 20hp Evenrude won't idle

G Dane's advice sounds good. Worth a try at least.<br /><br />Forgot that in '89 they used the same block.

 

[G DANE]

Re: 1989 20hp Evenrude won't idle

Well since you know, not only of a bunch of different models, but also many different brands of outboards, its obvious that you have to forget a detail now and then, JB. I only know of Johnnyrudes, and the early to mid eighties 25 - 35 HP' in specific, so I have less to forget. Besides I know half of what I know from you, you helped me out of my broken reed problem I couldnt figure, years ago, still owe you one for that. I havnt been able to let an outboard alone since, rides me like a mare. I am looking to get a 1956 Evinrude now, the year I was born, definately one of the best vintages !!