Help with Carb problems, Please.

[tkmichael11]

My engine is a 1980 228 in a Sea Ray. I've been having the same issue now for two seasons and cannot seem to figure out the problems. First, the engine runs great when you first start it. It will come up on plane and run as strong as a new boat. 4100rpm at full throttle and very smooth! Once the boat has been running for 10-20 minutes and you shut it down, it is very hard to start and when you do get it started, it will idle but when you give it throttle, in gear, it spits and coughs and backfires until you drop it down to neutral. It will then idle rough for a few seconds and die. To date I have replaced the following: Plugs (when I just changed the plugs, they were black but dry), wires, cap, rotor, points changed to ignitor I, coil, and added a reman. rochester qjet. I did a compression test and all cylinders are within specs. Timing is set at 8 BTDC and the air/fuel mixture is set at 2 1/2 turns.

I am at the end of my ropes with this one! I am almost ready to get rid of the boat but I keep thinking there is something small that will fix this issue.

 

[WAVENBYE2]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Sounds like its not (set right) still, Gaps could be off" Manuals gave me 2 diff. settings. Carb might not be adjusted right or or you throddle is not right at wot (too far advanced) maybe, sounds like you have something off, What Manual are you using, Hopefully not a Seloc, that could explain it lol, Other guys can help, I wanted to reply due to I do all my own(mostly) work myself and have gotten just as frustrated, Good luck

 

[Bifflefan]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

To date I have replaced the following: Plugs (when I just changed the plugs, they were black but dry)

Well theres a problem. The plugs shouldnt NOT be black. Thats eather a rich fuel mix or lack of spark to burn the fuel.
Quad's are notorious for leaking jet plugs. Even in a rebuilt one.
Me I'd try a different carb. Borrow one from a friend that is known to be a good runner and see what happens.

 

[P 0 P E Y E]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Black usually denotes rich mixture. I would first check the choke to see if it is operating correctly, does it fully open when engine is warm, is the choke plate being pulled closed at high rpms?

IS this problem the same problem you had before you replaced a bunch of parts?

I always suggest.......Check your distributor's spark advance for proper operation.

 

[chunckj]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

I'm not a marine mechanic but I am an automotive mechanic and i have never gotten a rebuilt carb that has been set right. Normally the floats are way off. Will finally run good? if so maybe a bad check valve letting fuel drain back into the tank. good luck

 

[tkmichael11]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Thanks for all the great info. Im in the process of looking for a carb to swap.

 

[tkmichael11]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Im looking for some advice on which carb to purchase. So far I found a reman. Mallory and another reman. qjet. From what I've been reading, the qjets have been notoriously problematic. Would I be better off going with the Mallory and forget the qjet or try the qjet again and hope this one is adjusted and reman. correctly?

 

[Meauran]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Try using a more descriptive title for your problem thread. That would be my first suggestion.

 

[tkmichael11]

Re: PLEASE!! Help me!!

Re: PLEASE!! Help me!!

Try using a more descriptive title for your problem thread. That would be my first suggestion.

I can't see where that would help with my problem, but whatever helps you sleep at night

 

[Greg Gessler]

Re: Help with Carb problems, Please.

Check your float level (sounds like it could be too high) also check your needle and seat that they are sealing properly.

 

[PiratePast40]

Re: Help with Carb problems, Please.

Sometimes my computer messes up and doesn't display some of the posts in a thread. I must have missed what happened when you did as Popeye suggested concerning the choke and timing advance. Could you please repost that? Or perhaps you took Bubbas advice before you decided to buy another carb and we missed what the qualified marine mechanic told you.

 

[jtybt]

Re: Help with Carb problems, Please.

Check choke first. make sure it's opening all the way. The Q-jet can get a sticky float valve. Whack the fuel inlet with the plastic or wooden handle of a screwdriver to try a jar it loose.

 

[futz]

Re: Help with Carb problems, Please.

carbed motors should be started and stopped in a old school way.

First when you start, pump the throttle 2-3 times in neutral and leave tghe throttle 1/3 of the way advanced. Crank it over for no more then 10 seconds, if it doesn't start, let go of the key wait a few seconds and try it again, no more then 3 tries.

If it doesn't start in 3 attempts of step one then there is something wrong.

When you take off from the dock take off slow, actually whenever you take off unless your pulling a skier.

When you go to stop, stop slow pull back the throttle slow, and allow the motor to idle for at least 3-4 minutes, and then shut her down.

One other thing prolonged idle, say for hours at a time is a bad thing for a carbed motor.

 

[Wet Wonder]

Re: Help with Carb problems, Please.

I'm not an expert, and still just learning about engines-but from your post the difference between the motor running right and running poorly is that it ran well when warming up, and then ran poorly when hot. Based on that, I thnk you should first check the choke before messing with the carb. When your on the water, watch the flaps and make sure they're opening correctly. I'd rule that out first. It just doesn't sound like carb on first glance.

 

[tkmichael11]

Re: Help with Carb problems, Please.

I have another carb being delivered on Monday. I checked the choke and when the engine is warm, the choke is opened fully. Right now I'm just running the boat in the driveway (with muffs) and I really think this is a carb issue but when I bought the boat, I took it out on the water and it ran great for 15 mins. We pulled into a cove, fished for about an hour and when I went to start it, it was very hard to start and when it did finally start, it was spitting and backfiring and it got worse with more throttle. Well, I got it home and gave it a full tune up, which included a new coil and upgraded from points to ignitor ignition and swapped carb with a rebuilt. I put on the rebuilt and the boat did the exact same thing. The only difference was, when you look down into the carb you could see fuel pouring into the engine, and this was at idle. I was told that is not normal and swapped carbs again. This time, when the boat was idling, you could not see the fuel pouring into the carb. I figure the problem is fixed and take the boat out. Well it runs like a new boat for the first 15 minutes then starts to backfire through the carb and has no power. Every once in awhile, it would surge but then it would go right back to backfiring through the carb. Like I said, I have another carb coming on Monday. It's another rebuild but this time its from a different company.

This is very frustrating but I really appreciate all the great advice!

 

[Wet Wonder]

Re: Help with Carb problems, Please.

If its back firing thru the carb, double check that you don't have a couple of plug wires crossed on the firing order.

 

[wca_tim]

Re: Help with Carb problems, Please.

had you thoroughly cleaned the carb and checked for water? changed out water separator, etc...? could be junk stuck in nedle valves, or even water in the carb wreaking havoc. if needles aren't sealed, engine will run ok for a little bit... and then the bowl overfills and starts dumping gas into the intake, and so on...

If it's a fuel contamination issue, the new carb will only solve it for a while... hope it works out either way.

 

[jtybt]

Re: Help with Carb problems, Please.

I told you how to unstick a float valve.