1957 Sportwin Won't run on low idle

[flexon_guy]

I can get this 10hp runing well at high speeds but when I try to bring the throtle down it kills. There is no low idle. Also it seem as though it is running a little lean. Sometimes I have to pull the choke a little to get it to keep running. I Decarbed it a couple of times. But this did not help. After running it for 10 mins. so much presure built up in the tank that it ruptured the fuel line. Is this abnormal preasure? Is there some preasure release valve on the engine or tank? After close examination the fuel and air line need replacing but should there be this much presure?. Are these two problems interelated or does this sound like the carb needs to be rebuilt?

 

[Chinewalker]

Re: 1957 Sportwin Won't run on low idle

Hi Flexon-guy,<br /> It sounds like you've got two different problems. First, the carburetor will have to come apart and get thoroughly cleaned and blow out all passages. The low speed circuit is probably plugged up.<br /> Second, your tank is supposed to build up pressure. How old is your fuel line? If it is old and shows check-marks when you bend it with your fingers then it'll need to be replaced. A johnrude dealer ought to have the hose onhand by the foot.<br />- Scott

 

[55Crestliner]

Re: 1957 Sportwin Won't run on low idle

Have you had this motor running good at idle before? Or is it new to you?<br />Did you adjust the idle mixture(top one)?<br /><br />I had the same trouble, just needed the mixture richened up, more than what the cover in place would allow.

 

[flexon_guy]

Re: 1957 Sportwin Won't run on low idle

I bought this engine from a guy who stated that his granfather had gone throuh it and had it running well and he had it out and it worked for him. I assumed he had it recently out. When I started it on the lake it started with allot of effort and then choughed allot and missing. Then all of a sudden it kicked in and I was able to run it at high speeds with great power and speed for what I thought a 1oh.p. would have. The engine was not missing. Then after warming up I thought I would adjust that low idle for trolling. Engine killed. I had a dificult time getting it started, when it kicked in I took it back to the dock. The next day I tried a decarb and could still not find that low idle. While doing this the fuel line ruptured three times which became apparent that it needes a new fuel/air line. This is my next step as well as a carb rebuild. I just was'nt sure if maybe the high or low presure of the fuel lines were not dependable could have caused the low idle not to work.

 

[flexon_guy]

Re: 1957 Sportwin Won't run on low idle

55Crestliner <br />I did have the top idle set at three which seemed like the sweet spot.<br /><br />What do you mean by needing the mixture richened up more that what the cover in place would allow?

 

[R.Johnson]

Re: 1957 Sportwin Won't run on low idle

On this engine, I would take a look at the ignition coils. I'm betting their cracked, very common on these old motor's.

 

[55Crestliner]

Re: 1957 Sportwin Won't run on low idle

I certainly don't claim to be an expert, your motor could have other problems, (mine also needed the coils) but yours, like so many others on this board, sound like the same symptoms as what mine had. <br /><br />I did the adjustments to the needles like I was told to do by the shop manual, and the carb rebuild kit, (as in how many turns to unscrew the needles). But my 1955 10 horse would not run correctly at all. As you've already noticed by mentioning you have it set at "3", it is in the middle of it's range -with the face plate in place- MY motor needed it's screw turned counterclockwise beyond what the faceplate would allow. All I know is that for ME, I had to unscrew the needle almost another full turn to get it to run right. <br /><br />I don't know why it needed more "unscrewing" than what I was told, but it runs VERY well at slow speed.<br /><br />If I were to have to go through this again, I would just turn the top lever all the way clockwise, see if it works. If not, loosen the lever screw and rotate the lever clockwise (without rotating the needle), then tighten the lever screw again, then this will give you another 1/2 turn to play with. This is easier than removing the face plate like I did!