63 fastwin 18hp idle

[craveman85]

i have a 63 evinrude fastwin 18hp. it doesnt seem to like slow speeds much. if i throttle down to the idle screw on the throttle it would always stall out. it is pretty shakey at idle and paritial throttle till i get into the high speed circuit. so after some pondering i took out the low speed needle. the washers were disintegrated in there. i cleaned them out and put in some new washers with an o ring to seal it better. i put the needle back in and backed it out the standard 1.5 turns but it wont start at that setting. about 2.5 turns out it starts and will run at a higher rev and at 3.5 turns out i can idle it all the way down with the idle screw at the maximum rpm setting. any suggestions. i can still putt around with the boat just fine but just cant get the really low rpms and im not sure why the needle needs to be out 3.5 turns.

 

[jbjennings]

Re: 63 fastwin 18hp idle

Either the carburetor is still clogged, or you have a vaccuum leak somewhere. Or, you have a motor running on one cylinder because you don't have spark on it. See if it will run with the top plug wire grounded, and do the same to the bottom. If it will run with one wire grounded, but won't with the other, then one cylinder is not getting spark. Bad coils are a typical problem if they're old.
GOod luck,
JBJ

 

[lindy46]

Re: 63 fastwin 18hp idle

If it's running fine at high speed, then your low speed circuit is probably gunked up. I'd remove the carb, clean it and install a new carb kit. Make sure to remove the welch plug on top if the carb. The low speed circuit is under there and there are some small holes which clog up. Clean that out well and reinstall a new welch plug. That should solve your idling problems.

 

[craveman85]

Re: 63 fastwin 18hp idle

i cleaned out the carburetor again and did a full rebuild.i let it sit in my ultrasonic cleaner for a few cycles too. it seems that some of the disintigrated washers made their way into the low speed jet and plugged it up a bit. it runs slower now but its still kinda shakey.

 

[kfa4303]

Re: 63 fastwin 18hp idle

If carb is clean, then I'm thinking an ignition/spark issue too. May need to clean and readjust the points to get good strong spark. these motors can start and run surprisingly well on just one cylinder. Make sure the brass bushing that the hi/lo needles pass thru are snugged down properly too. If tweaking the carb doesn't help, you may want to check the compression to make sure it's where you want to be. In any event just change one variable at a time and see what happens, other wise you'll start chasing your tail and running in circles.