1958 sportwin will not idle

[kawk]

hi,
this old beast used to idle at troll speed all day long. now not at all. goes great at wot but sputters and quits at idle.
all the electronics were changed 2 yrs ago. carb was cleaned and rebuilt last weekend. upper crankshaft seal was destroyed(carbon type). replaced that seal with a new one.
when i tested in a barrel motor ran better, but not by much. when i try to set the low speed (turning it in) there is no rpm change. i will have unspent fuel when i run in a barrel. but the ammt this time was way more than im used to.
have i overlooked somthing on the carberator side? could i have a bad lower cs seal.
thanks,phil

 

[bktheking]

Re: 1958 sportwin will not idle

How did you clean the carb?

 

[kawk]

Re: 1958 sportwin will not idle

hi,
i cleaned the carb as described on this site. in short ,soaked in solvent and blown clean with compressed air. totally rebuilt the carb excluding the float. the float was changed 2 yrs ago. replaced the original cork float with synthtic type.

 

[bktheking]

Re: 1958 sportwin will not idle

Sounds like you may have garbage in your idle circuit still.

 

[lindy46]

Re: 1958 sportwin will not idle

hi,
i cleaned the carb as described on this site. in short ,soaked in solvent and blown clean with compressed air. totally rebuilt the carb excluding the float. the float was changed 2 yrs ago. replaced the original cork float with synthtic type.

Did you pop the little welch plug on top of the carb that reveals the low speed needle? Check the holes in there and make sure they are all clear?

 

[kawk]

Re: 1958 sportwin will not idle

hi,
welch plug removed cleaned and replaced with new.


bk, not exatly sure what an idle circuit is?

 

[tashasdaddy]

Re: 1958 sportwin will not idle

http://forums.iboats.com/showthread.php?t=299680

the idle circuit, is the small tube, inside the bigger tube in the center of the top half of the carb, the small tube picks up fuel for the idle circuit, also the chamber behind the top (slow speed) adjustable needle jet. you also may have a damaged, needle, if it is not pointed, replace it.

i assume you have replaced all fuel lines from carb to tank. read ethanol, adjusting, carb rebuilding.

 

[kawk]

Re: 1958 sportwin will not idle

hello tashasdaddy,
i have not replaced the fuel lines but i will now. still not sure what your talking about in regards to idle curcuit.
the low speed needle is brand new and still pointy.
i assume i should start over and re clean carb. its hard for me to believe that i missed somthing in the last cleaning. is there an area of this carb that is commonly overlooked? do u know if the welch plug is available or do i have to get the whole rebuild kit?
frustrated!

 

[Chinewalker]

Re: 1958 sportwin will not idle

Did the gasket at the base of the main jet get replaced? It is the thick, round cork or rubber gasket that gets sandwiched between the carb bowl and the casting that comes down from the center of the carb body. It is often overlooked...

 

[kawk]

Re: 1958 sportwin will not idle

hello cw,
nozzle gasket replaced with new one from rebuild kit. it is thick.
i took the carb off and its soaking in carb cleaner. i'll leave it over night.

with every thing ive read here at iboats it sounds like i have a carberation problem. i will work that angle first. new fuel lines and a new welch plug

does anyone think that the lower seal maybe a contributing factor? would the massive amt of unspent fuel be coming for a bad seal? or the fact that the motor was running so poorley= unspent fuel?
phil

 

[Willyclay]

Re: 1958 sportwin will not idle

Phil, when TD and Chinewalker post, I pay attention. They are experts and have helped me on numerous occasions. However, my experience with a 1959 Big Twin was similar to yours. It would start easily and run great but idle poorly. After two soaking/cleaning and rebuilds, it still woud not idle. Finally, after a third cleaning I found some real hard crud in the low speed needle valve passage that could only be removed with a pick. Hang in there, it's usually something simple. Good luck!

 

[kawk]

Re: 1958 sportwin will not idle

hey willy,
thanks for the encuragment! the folks on this site are the best. TD and others helped me bring this old blue beast back to life once before.
frustration has got a hold on me right now but im confident that there is a fix. that fix will come from this site.
phil

 

[kawk]

Re: 1958 sportwin will not idle

Still wont idle.
cleaned carb again, plus bought a servicable carb off ebay. rebuilt and cleaned 2nd carb. change all lines from carb to tank.
I've tried both carbs and there is no difference between the 2.
the motor starts up fine and will run smooth at just above idle. but as soon as i try to slow it down to idle it goes rough. almost like the motor shuts off for a second and starts again.
what am i missing?
thanks in advance.

 

[samo_ott]

Re: 1958 sportwin will not idle

Air leak at the carb to manifold gasket?

 

[1946Zephyr]

Re: 1958 sportwin will not idle

I would check and make sure the points are gapped right. Sometimes, the gap will get smaller as the heels of the points wear down. You said that you replaced the whole ignition system a couple years back, so it might be a good idea to check the points.

 

[kawk]

Re: 1958 sportwin will not idle

hi z,
this thread is kinda part 2 of the probs ive been having. the upper seal on on the crank shaft went(carbon type). the entire electronics(coils ,points etc) was drench in oil. that seal was replaced and the electronics cleaned and dryed. i reset the points before putting fly wheel back on.

hi sam,
i replaced the manifold gasket . there was a new one in the carb rebuild kit. how would i check to find a leak?

 

[Maveric7383]

Re: 1958 sportwin will not idle

I would say you have a vacuum leak. any color difference between spark plugs? I would bet you have a vacuum leak somewhere. I had the same problem as you. I went through all the motions of making sure the carb was clean, decarbed the engine, checked timing, changed plugs, compression test, vacuum leak search. found slight color difference on the two spark plugs plugs. found bad lower crank seal.

 

[kawk]

Re: 1958 sportwin will not idle

hi mav, im gonna try and find out if that lower seal is bad. i've never taken a powerhead off before. do you have any advice, tricks, warnings?
phil

 

[kawk]

Re: 1958 sportwin will not idle

im going to attempt to check my lower crank case seal. does anyone have any advice (warnings) on removing the power head. i've never done this before.
phil

 

[Willyclay]

Re: 1958 sportwin will not idle

Phil, I'm OOT and don't have access to any service info for a few more days. Do you have a manual to help you dig into that motor? Please post the model number. Thanks!