Need help with a Comer 50

Ronald Zouein · Joined: 25 Oct 2012 Posts: 2

Hey Folks,

My son's recently started racing, did his first meeting a couple weeks ago and the kart failed us after a very strong practice session.

What happens is that the engine takes time to start. You pull on the string quite a few times and you feel the engine is kinda choked. If it starts, the minute he hits the gas the engine chokes and dies. If it doesn't die it kinda bogs. Not sure what the problem is.

Secondly, would love any tips you've got that we can apply to optimize the power of the kart. Obviously within regulation. Can't change the 58 Jet, nor the 85 sprocket/gear. What else can we do?

Appreciate any advice.

Cheers,
rz

marc-andre hubert · Joined: 10 Apr 2012 Posts: 174

make sure carb is clean first of all, then when hard to start probably have a lean jet, if i run the 56 jet to make it start good, i need to close the choke plate a bit then starts right off, again being lean and not up to temp, cht at least 200f kart is a dog off the line,but once it goes runs awesome, but if i run richer 57 all is good, check those basic stuff, then we can check other things

Oscar Biondi · Posted: Mon Oct 29, 2012 1:15 pm Post subject:

Sounds like it's carb rebuild time

Ron Dodson · Joined: 27 Aug 2009 Posts: 51

I've been having a similar issue. I try to rev it up a bit before shutting it down. When I start it I hold the brake and then hit throttle until I can get it to rev without bogging. Usually take 5-10 times. And we're not talking about reving the think to 12K, just until it revs up without the bog.

After I put it on the ground and he gets in, I tend to get it a few times to check and then he's good to go.

FWIW, I do believe it is related to the carb. My old carb never did this but after it broke, this new one I just bought does it all the time.

Steve Moody · Posted: Wed Oct 31, 2012 9:23 am Post subject:

I'd pull the carb off and clean it really well with carb cleaner and check the plug since these engines can foul up a plug very easily.

Then next time you're out there start it (with the choke on if needed), then let it warm up for a couple of minutes before he goes out on track. My son's kart does the same thing until it's warmed up, then it runs well. Just don't forget to open the choke before you send him out, been there, done that Laughing

For now I wouldn't mess with trying to get more power out of it, since any gains will be minimal. The best thing you can spend money on is track time. Get him comfortable in the kart and learn to adjust the chassis, that will do more for lap times than a bit more HP.

Stewart Willis · Joined: 24 Oct 2008 Posts: 366

To restate what some others have said, Most issues with the C-51 are carb related. Once you clean out the carb (and change the spark plug), see how she goes.

You mention that you feel that it is being choked, which is feeding too much fuel (not enough air). However, what it sounds like you are describing is just the opposite. What I would suggest is starting the engine with it choked or partially choked. Rev the engine a bit on the stand. See if it sounds better partially (ever so slightly) choked vs. fully unchoked. If it runs better choked, then you have an air leak. Most likely this is caused by crankcase seals... spray an ether (starting fluid) down by the seals and see if it changes RPM. If so, then you know where the leak is. If this is it, change the crank seals...

Hope that helps.
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Stewart Willis

Jose Martin · Joined: 05 Mar 2013 Posts: 6

Usually the rules (WKA) call for an 89 sprocket instead of an 85 and the jets up to 58.

Somethings that will help us is whats your fuel mixture like?, K&N filter or stock filter, spark plug gap? jet?