hawkeye625

4.3 mercruiser issues

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Ok, I just found the receipt from the mechanic in NY.  The receipt has 1 fuel pump, 1 electric amplifier $598(module I'm assuming) 1 carb kit.  The cap, rotor, coil and distributor module were replace by a marine mechanic here in PA last year.  Both guys are certified and timed the engine when they had it.  Plugs were replaced this year as well.

 

At this point, I am just going to take it to my "certified" mercury dealer here in PA come spring.  Just figured someone may have had the same issues.  Hopefully it is just the timing.  I'll update when I get it strait in a few months.

 

Nothing more frustrating that boat issues.

 

 

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I have had some issues like this in the past.  The one time, it was a dead bug in my fuel tank that kept getting sucked onto the pickup tube in the gas tank.  The next time, it was the inline filter at the carb (full of particulate).  This past season, the flame arrestor on the carb was full of cotton wood.  All stupid little things that caused the same symptoms.  Just some other little things to check. 

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On 1/12/2018 at 2:14 PM, hawkeye625 said:

Fuel freshness varied throughout the year, but, all new now.  We also ran it on new gas from a portable can and it ran the same.

What gas are you using . 91 Octane Non- Ethanol Gas solved all my problems , been using it for years in all my Toys and yard equipment.

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19 hours ago, GAMBLER said:

I have had some issues like this in the past.  The one time, it was a dead bug in my fuel tank that kept getting sucked onto the pickup tube in the gas tank.  The next time, it was the inline filter at the carb (full of particulate).  This past season, the flame arrestor on the carb was full of cotton wood.  All stupid little things that caused the same symptoms.  Just some other little things to check. 

 

This story reminds me of something, in the tank there is a check ball valve, and one time I had the exact same issues. I had this damn boat everywhere then buy dumb luck I was reading in the manual, and came across this, I pulled the floor up and I had to unthread this metal tube from the tank and what I found was this tube has a metal ball that just rolls back and forth and keeps all the fuel from draining back into the tank. Well this ball only moved half the ball away from the end of pick-line and starved the motor of fuel. Sprayed carb cleaner in there and ran a small bottle brush in the tube cleaned her out again put everything back together and problem solved, such a stupid little thing like that aggravated me for a year before I figured that out. That never gave me a bucking the starter like you mentioned though?? What year is your boat???

Edited by pap

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Yes I've had my share of crazy things happen too.  Mud wasps in the breather tube have given me trouble in the past.  That's why I started the thread.  Figured it might be something stupid, but, being the mechanic ran it off a portable can, most of the fuel issues should be eliminated from the "problem" list.  Of course now I'm running off my main tank, it could be an issue again.  Oh the joy of boat ownership.

 

Pap, it is a 1992 Crestliner Sabre.

 

Just to clarify, I'm not bashing any mechanics or anyone's ideas - just trying to fix the boat! 

 

 

 

 

 

 

 

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On January 17, 2018 at 2:28 PM, GAMBLER said:

I have had some issues like this in the past.  The one time, it was a dead bug in my fuel tank that kept getting sucked onto the pickup tube in the gas tank.  The next time, it was the inline filter at the carb (full of particulate).  This past season, the flame arrestor on the carb was full of cotton wood.  All stupid little things that caused the same symptoms.  Just some other little things to check. 

 

I went thru all this also including pulling the pickup tube and completely draining the tank and filling with fresh fuel. In the end it was timing. I discounted the timing because it would idle and up to 3000 rpms just fine, after that it was rough and cutting out. My buddy says boats have to be adjusted under load? Don't know but it sure fixed my problem. 

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Your story of timing and the above problem motor is why I said that fuel symptom shouldn’t make the starter buck, especially when the motor is cold. I had a guy come to me with a similar problem where he had 2 issues first was he said his boat hesitated trying to get on plane then was fine till the next day, the starter bucked then spun fine. What I found was water droplets on all 8 plugs?? What the hell thats impossible, how could both head gaskets go bad at the same time?? I assumed a water problem since the starter bucked cold, kinda like a weak hydro lock. So we pulled a head gasket was fine?? The only way water could get into all 8 cylinders is through the fuel system, but the owner said they drained the tank and there was no water in the fuel!! Well then the only other thing that feeds all eight cylinders is the intake manifold, so I pulled the intake made plates to close off the runners and a plate where the carb sets and added air and you could hear a hissing sound. So the intake where the thermostat sets rusted through and water was getting put in each cylinder at a minimal amount, but when it sat water would leak into the front cylinder just enough that it would create a slight buck in the starter then it pushed the water out the exhaust valve and it went away for a little while. Switched out the intake and all is well!! LOL

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The accelerator pump in the carburetor is now twenty six years old the rubber could be deteriorated. Look to see a squirt of gasoline in the throat of the carburetor when you open the throttle.


Sent from my iPhone using Lake Ontario United

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Had a bumblebee in my tank the size of a big mans thumb. That made for a interesting summer.


Sent from my iPhone using Lake Ontario United

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Hi,

 

I had this type of problem once on the 4.3 of my Princecraft Corsica. I just bought the boat and took it to a marine dealer for a full check up and tune up. I took the boat to the lake for my first run... It ran fine on idle but when i gave it some throtle it wouldn't take the gas. I tried different things with no success. I finally got back slowly to the marina launch and told the marina owner my problem and i decided to leave it for their mechanics to look at it. They called me back a few days after and told me that one of the ignition wires was on the wrong cylinder so they reviewed the correct sequences and timing. After that it ran great. I hope this can help. :):) 

 

Robert

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Also in the pickup tube the 90 degree fitting comes apart and their is a small mesh filter that plugs as well. Also consider how old the main fuel line is! My main fuel line was bad on the inside and would suck it's self closed at higher RPMs and eventually at all RPMs . Date is printed on the fuel line itself along with fuel line type. Should check fuel line regardless if it's an ignition issue to to prevent future problems.

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Just to update, it was the timing.  Not sure how it got out of time on the ride home, but, it was.  Next weeks derby will be the true test.  If she makes it through, I'll be happy.

 

Thanks for all the replies.  I'll keep you posted if my issues continue.

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Had a similar issue on mine a few years ago - it was the tank vent screen that was clogged in the anti-siphon valve.  

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Glad to hear you got it fixed. It can be frustrating for sure. Good luck in the tournament. 

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