Carb not staying full? (bulb goes soft)

CaneCutter79

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My motor type/model/etc is below in my signature.

I had the motor rebuilt earlier in the year. I've had to take the carb off and clean it once already as it had trash in it (looked like part of the fuel line? really tiny black rubber). Ethanol fuel could be eating new fuel hose that was replaced with new EPA approved fuel line during rebuild in Feb. this year.

After having problems starting the motor cold or warm, I've finally found that the bulb is not staying primed (hard). Is it the fuel pump or is there something possibly allow fuel out of the bowl in the carb that's causing this?

Should i go to the trouble and take the carb apart and clean again? Or is it the fuel pump?
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

does your engine keep running? The primer bulb will be soft after you start up and run.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

Runs normal and no issues once I can get it to run. If its running rough or just barely and if I hit the throttle forward in gear, it takes off and I'm good.
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

I don't believe that this has anything to do with your hard start issue. Seems like primer bulb is doing it's job and if it was the fuel pump you wouldn't take off and be good. I guess you just have to either live with your hard start issue after your rebuild or figure out what starting procedure it likes now. I have three different boats and all have their own quirks when it comes to cold starts.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

What about when the motor is already warm? I can run the motor for a long time and shut down for about 10mins or so and have similar starting problems. Runs rough until the carb gets settled in. You have to use fast idle to start and then back off of fast idle and let it run for a min and this repeats about 4times (fast idle, start/fast idle,start/ as it will run for a few seconds).
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

I would check the carbs one more time and change fuel lines to ethanol resistant. Also you should put a cheap inline fuel filter on it
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

It has ethanol resistant lines, it also has an inline fuel filter on it. I noticed today that I put the filter between the motor and the bulb on the tank. Thinking fuel may be draining back into the filter, I checked the bulb today by pumping fuel full till bulb could not be squeezed anymore. I checked again an hour or so later, and it was still hard but I could squeeze it a little. Several hours later, I could squeeze the bulb easily.

The amount of fuel that was inside the filter had decreased. So.....

A) Either fuel is leaking back into the tank and the bulb's check valve is leaking
B) The motor was trimmed up in the trailering position and fuel leaked out of the carb because of this (I doubt that's the issue)
C) Something is not right with the carb and allowing the fuel pressure to diminish quickly

Again, once you get the motor started, boat runs great. Great fuel mileage and performance. Just hard to start and acts like it's fuel starved.

I'm going to check the carb soon but I'm checking the bulb at this point. Amount of fuel should remain the same in the fuel filter in only a few hours. Also, no sign of leaking fuel under the cowling. Fuel is going somewhere so it's either back in the tank or it's inside the combustion chamber.
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

If it is tilted up for trailering fuel will drain from the carb bowls and back into the crankcase through the line at the bottom of the air silencer.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

OK, with motor tilted dow level, it still lost pressure in the bulb overnight. About 2.75 pumps on the bulb to fill it up.

So I disconnected the fuel line from the engine. After only 2hrs, the bulb could be pumped about 1/2 pump. So in my mind, the check valve within the bulb is seeping and allowing fuel to leak back into the tank. I don't think that's normal. It shoudl stay pumped full for much longer.

So, could this be the source of my odd start problem? I doubt it. It's probably still the carb needing cleaning but this could also aide in the issue.
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

The bulb on all three of my engines will go soft overnight. I don't see where it is a problem to squeeze it three times and the engine starts. I really don't see this as a problem. Instead of using your fast idle you can just bump the choke/primer a couple of times and it will accomplish the same thing.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

I'm pushing in the choke while is I g fast idle just to get it started. Once it starts, it often makes a noise almost as if it were about to backfire (kind of a wheezing sound) and its starved for gas. Even minutes after running normally for hours.

It did this once before and it was trash in the carb. I was hoping it wasn't but sounds like it is. I need to inspect my new fuel line for problems. I'm suspecting it has pieces of it in the carb. Last time was a tiny black spec clogging the carb. Did all kinds of hard start issues with that tiny spec.

Thank you for your help. Looks like I need to check the carb and then go from there if problem persists.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

Quick update
I blasted the carbs with the air compressor after shooting carb cleaner into the carb and into the intake ports from the fuel pump. Evidently, that did the trick and I don't have to take the carbs off and manually clean them.

Motor starts now on the hose without any hesitation. I haven't tested it on the water yet but I think its good now. I suspected the carbs all along but did t want to have to take them off and service. Just a lot if work and wear.

Just started up the motor during my lunch break as the motor was as cold as it could get. Started instantly. Its NEVER started this easy so I'm pretty happy.
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

Glad to hear it. Make sure you have an inline filter so you don't pick up crap from your tank again.
 

CaneCutter79

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Re: Carb not staying full? (bulb goes soft)

Yes I do. Its been on there for more this. Rather surprised the carb had trash. Fuel in filter looks clean.
 

fireman57

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Re: Carb not staying full? (bulb goes soft)

Could be the lines going to the carbs are breaking down from the inside.
 
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