It never ends!

U

Uraijit

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Feb 5, 2008
Messages
884
So after fixing about a billion other problems, I had to pull the engine and replace the oil pan gasket. So Everything was running GREAT except for dumping oil in the bilge.

Got the engine back in last night, put it on the water today. It ran for 3 min. while my wife idled around in the marina while I parked the trailer. Engine died, and wouldn't restart.

After getting towed 100' to the dock :redface: I messed around with it. Fuel bowls were dry. I tried cracking the fuel line from the carb, and cranked it over. Fuel started spraying, and it fired up.

I decided to go ahead and check the fuel filter on the carb, and it was clean. Put it back together, it fires right up, and idles out of the marina.

When I go to open it up, it's absolutely gutless! It would barely hit 2000 rpm. Messed around couldn't get anything to change. I tried opening up the secondary butterfly valves manually, and got a big backfire...

Went through the list, and it's looking like I'm gonna have to rebuild the carb... Anybody think of anything else I should check?

* Fuel condition. Type and Octane possibly old fuel Good fresh, clean fuel.
* Propeller pitch or diameter, damaged blades Nope
* Restricted fuel pickup tube or anti siphon valve Fuel System TestClean and clear
Crankcase oil volume, high oil level can cause aerated oil and lifter collapse Full oil--not over full
* Marine growth on hull and outdrive Nope
* Wrong gear ratio in outdrive Nope
* Restricted carburetor air intake (clogged flame arrestor) Nope
* Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive Just checked them when I had the engine out.
* Poor cylinder compression Compression Test still good.
* Carburetor defective, or wrong type. Deffective? Maybe, but it was fine before.
* Fuel pump pressure and vacuum Gotta check that.
* Boat overloaded, improperly loaded, or improperly trimmed. Nope
* Engine Overheating Nope
* Engine timing and ignition system operation Nope
* Remote control cables and linkage for proper travel to open throttle plates fully. Fully opening.
 
U

Uraijit

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Messages
884
Re: It never ends!

Timing's good, compression's good, pretty much everything internally is good. Like I said, it was running like a top before I pulled it out. So internally, the engine is sound.

I'm convinced it's a fuel delivery issue. Hoping it's something simple, since it's a Q-Jet, and I've never touched a Q-jet. I hear there are way too many parts to allow for a quick easy rebuild... I really don't want to have to tear this carb apart.

Hoping it's a stuck float, as suggested by driller...
 
K

KJSmitty

Petty Officer 2nd Class
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Aug 9, 2008
Messages
179
Re: It never ends!

Uraijit said:
Q-jet. I hear there are way too many parts to allow for a quick easy rebuild... I really don't want to have to tear this carb apart.

Hoping it's a stuck float, as suggested by driller...
Click to expand...


Don't fear a Q-Jet :)

Not too different than any other carb rebuild - but you are right there are a few parts and pieces. :) Just be careful not to damage any of the metering rods, or loose any of the small check balls. Most rebuild kits contain good pictures and aids etc.

You very well could have a stuck primary metering rod "power piston". This would keep the primary metering rods from lifting out of the primary jets, starving/leaning out the engine (or flooding it prematurely once off the idle circuit etc). I've seen many situations like that when a Q-Jet sits for a while etc..

A stuck power piston however doesn't quite explain the engine dying all together however. Did it act flooded once it re-started?

As you stated, might be the float - complete rebuild may be in order - or at least an upper gasket and float kit etc.. IF you do tear it down I would replace the float and needle/seat. It's been a while so I don't remember if the float came with a complete kit or not. Tis too much work to get it all adjusted then back together and find the float is sinking a bit.. No way to adjust the float externally either. You use a small paper scale while the carb is separated.


Good luck
 
U

Uraijit

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Messages
884
Re: It never ends!

The fuel bowls were totally dry after it died (couldn't get the accelerator pump to spray). I cracked the fuel line to prime the pump, and it seemed to work. Engine ran great after that, at idle, but was just a turd at anything over 1000 rpm. Wouldn't get over 2000 RPM.

Maybe I jarred the float just enough, while monkeying around with the fuel line/filter, that it's partially filling, but not completely? I don't know... I'm not really a carb guy.

I'm seriously considering just scrapping the carb, and throwing in a TBI system.
 
E

EarlyWood

Seaman
Joined
Jun 11, 2008
Messages
64
Re: It never ends!

it's okay..
we're in the same boat

god i frkn kill myself


oh yeah, if i could help you, i would
 
K

kellydee

Petty Officer 1st Class
Joined
Feb 24, 2007
Messages
207
Re: It never ends!

B.O.A.T. BREAK OUT ANOTHER THOUSAND!! No matter how many of those I put in her(thousands),she always wants more.Hmmm,where have I heard that before?
 
JustJason

JustJason

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Aug 27, 2007
Messages
5,321
Re: It never ends!

urijait said:
The fuel bowls were totally dry after it died
Click to expand...

well... if you were sure your fuel bowl was dry, then you know you have a supply problem.
 
K

kellydee

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Feb 24, 2007
Messages
207
Re: It never ends!

Maybe I jarred the float just enough, while monkeying around with the fuel line/filter, that it's partially filling, but not completely? I don't know... I'm not really a carb guy.

I'd agree with this except,the prob is when the bowl fills all the way,it sticks.when fuel sits in the bowl for a while,it turns to like a varnish.Very sticky.let it dry,crusty.Clogs the small holes everywhere.I'd rebuild it as once it has gotten this far,even if you get it freed up,it can become almost impossible to obtain or maintain fuel:air mixtures due to this sticky,small particle scenario.Just my opinion but,beats the hell out of having probs every time out.Plus,you'll only pull the carb and dismantle it 1 time(if properly done).I'm assuming the fuel pump is ok("Fuel started spraying, and it fired up")but there are WAY more qualified than myself here.If Don S or Bondo respond,pay attention and don't question.Coupla guru's.
 
D

DJ

Guest
Re: It never ends!

What about the anti siphon check valve at the tank outlet?

Did you remove it for testing?

Your "Cracking" the fuel line open would/could have freed it.
 
U

Uraijit

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Messages
884
Re: It never ends!

Yea anti siphon is fine...

How would cracking the line at the carb affect the anti siphon valve?
 
G

Genestealer

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Jul 20, 2008
Messages
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Re: It never ends!

I had problem almost similar to that.
First changed the fuel pump, problem solved but not for long.
Check if there is no trash in your fuel tank, like sand or something like that. It blocks your fuel line when you apply throttle, and when engine dies the sand falls back to the bottom of your fuel tank. I didn't clean my tank, just had to remove the net that attached to the end of the pipe that goes into the tank, fuel filter will do the rest.
 
D

DJ

Guest
Re: It never ends!

Uraijit said:
Yea anti siphon is fine...

How would cracking the line at the carb affect the anti siphon valve?
Click to expand...

You relieved the vacuum.

Don't over think this. If the float bowl is dry, it's not getting fuel.

How do you know the check valve is fine?

How about the tank vent?
 
U

Uraijit

Banned
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Feb 5, 2008
Messages
884
Re: It never ends!

Sorry, I'm still not seeing how "relieving vacuum" would affect the valve. It only works one way.

I know the valve is fine because I checked it.

As I said before, the bowl WAS dry. It's got fuel in there now. How much, I don't know...
 
Fishermark

Fishermark

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Oct 19, 2003
Messages
5,617
Re: It never ends!

Uraijit said:
Sorry, I'm still not seeing how "relieving vacuum" would affect the valve. It only works one way.
Click to expand...

And which way is that? Many people think the valve is there to prevent fuel from going back into the tank. It is not. It is there to keep fuel from coming OUT of the tank if you develop a leaking or cut fuel line. The fuel pump normally overcomes the resistance of the valve. If the valve gets stuck, your fuel pump would not be able to overcome the resistance.

Now, would "relieving vacuum" make the valve work? I don't know.



Uraijit said:
I know the valve is fine because I checked it.
Click to expand...

And how exactly did you check it?
 
U

Uraijit

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Messages
884
Re: It never ends!

Actually, the anti-siphon valve serves BOTH of those purposes. Prevents siphoning as it's main function. Prevents back-flow as an added bonus...

If you must know, it was really more of a check FOR an anti siphon valve, than a check OF the valve.

The previous owner had removed the check ball, and spring. This is how I know it's not the problem. THERE ISN'T ONE CURRENTLY ON IT!

I plan on putting one back on it, but for now, I can absolutely, 100%, totally and completely, unequivocally state that it is NOT the anti siphon valve. :D
 
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