'57 Fastwin - No High RPMs

[vote4me4pres]

I have an 18 hp evinrude that runs smooth, idles nice, but won't open up. As I increase the throttle it picks up speed and RPMs all the way through, but never gets to WOT RPMs. Doesn't sputter like its not getting fuel, there is just no more throttle left to give it. Tiller handle has only about 1/4 turn from stop to top. Any thoughts?

 

[jbjennings]

Re: '57 Fastwin - No High RPMs

Running on one cylinder because of weak or non-existant spark on one of the cylinders, or bad compression. Check both. Check the spark with a spark tester, not just grounding the plugs on the block-that won't tell you what you need to know.
JBJ

 

[crxess]

Re: '57 Fastwin - No High RPMs

Is this a new to you motor?

If everything mechanical checks out, consider prop pitch may be to high for the boat you are using it on.

 

[bill1134]

Re: '57 Fastwin - No High RPMs

Hi remove the cowling,on gear shift side there is a lever that moves when you shift gears that stops the throtle from moving to much in neutral or reverse .There is a adjustment screw that moves the lever Put it in forward gear and adjust it so that the throtle stop can past the lever.

 

[vote4me4pres]

Re: '57 Fastwin - No High RPMs

Thank you all. I has spark. I still need to check compresion and check the adjustment. Thanks again.

 

[vote4me4pres]

Re: '57 Fastwin - No High RPMs

Compression mid eighties on both cylinders. Adjusted lever on the side - cowl was blocking it. It gives me more throttle, probably a 30% increase in speed but still not what I expected. Not getting on plane in a 15ft aluminum shallow vee.

 

[jdsgrog]

Re: '57 Fastwin - No High RPMs

Did you try adjusting the high speed needle valve? You may be surprised on how much more performance you will get by adjusting the needle valve. Here is the link to the "top secret file" on adjusting the carbs at the top of this forum:

http://forums.iboats.com/showthread.php?t=167352