4.3L Mercruiser starting problem

[jb71]

I recently acquired a 1989 Sea Ray with a 4.3liter V6 Mercruiser engine. I am totally new to boating/boating problems etc. The boat starts up fine and runs fine, however, after it has been running for a while (10-15 minutes or so) and I cut it off, it will not restart. Sometimes, I don't even cut it off it just cuts off at idle. Seems to be flooded...it eventually restarts after a long wait. I was thinking it might be the carb but according to my father-in-law (his old boat) the carb was rebuilt a couple years ago. Any suggestions other than rebuilding the carb??? Thanks

 

[metwrench]

Re: 4.3L Mercruiser starting problem

Why do you feel its flooded ? What are signs ?<br /><br />Just becuase a Carb was rebuilt couple years ago doesnt mean something has not gone wrong. Do you have idea what Type of Carb is on it ? <br /><br />When it Dies out, You sure its not a LACK of fuel ?? When it dies again, Try looking down the throat of the Carb while someone PUMPS the accelerator, You should see squirts of Fuel come in by the accelerator Pumps. Also when it dies does it Die SLOWLY or ver fast...This helps determine what it could be dying from ..

 

[1stoutboard]

Re: 4.3L Mercruiser starting problem

JB.<br /><br /> From my expereince with Mercruiser 4.3 , i can say that the Carb needs to be rebuilt. I am sure you have a Quadra Jet Carburateur 2 or 4 Barrell. Those types of Carbs need to be rebuilt every 6 months or so( maybe more or less). There is a website www.1-5automotive.com. They sell those type of carbs for $247.00 , then you get $30.00 for the old carb if you send it to them. That is not a bad deal. Remember you need a marine Carb not a regularcar carb. They are totally different. <br /> Good luck.

 

[jb71]

Re: 4.3L Mercruiser starting problem

john,<br /><br />the flooding signs are strong smell of gas...lots of gas in the carb...it is definitely getting fuel when the throttle is pumped...when it dies out it is usually at idle and just starts sputtering and finally goes out...when it does restart there is lots of smoke and strong smell of fuel

 

[jb71]

Re: 4.3L Mercruiser starting problem

hey 1stoutboard,<br /><br />yep i think you are right...it is a quadrajet 2 barrel...you think i should buy a whole new carb or attempt to rebuild the carb? (I have a friend who has rebuilt same type of carb who could help)...do you know any good sources for marine carb rebuild kits? Thanks

 

[bomar76]

Re: 4.3L Mercruiser starting problem

There is a website www.1-5automotive.com. They sell those type of carbs for $247.00 , then

Just curious...that link doesn't work, what is it again?

 

[bomar76]

Re: 4.3L Mercruiser starting problem

Never mind, googled it up:<br /> http://www.i-5automotive.com/page4.html

 

[akriverrat]

Re: 4.3L Mercruiser starting problem

sounds like it might be choke not opening. is there a wire/s going to choke cover?

 

[Wellcraft 89]

Re: 4.3L Mercruiser starting problem

Its a rochester 2bl carb and it is one of the simplest to rebuild ,get a kit and do it yourself<br />with a manual of course.It might just need a good shot of gumout in the tank and some good gas.<br /><br />The float maybe sticking open and flooding itself.<br />or choke plate as stated maybe staying closed.<br /><br />Rich

 

[jb71]

Re: 4.3L Mercruiser starting problem

i think the choke is working fine...it seems to be opening and closing when it is supposed to<br /><br />Rich, I think you are right about it being the Rochester carb...actually, I got some info that said it could be a Rochester or Mercarb...according to the info it is a Rochester if it has one idle adjustment screw and Mercarb if it has two (????or vice versa...I don't have the info in front of me now)...any suggestions on where to get a rebuild kit?<br /><br />Thanks

 

[Wellcraft 89]

Re: 4.3L Mercruiser starting problem

you can problably get them here ,not sure<br />mercrusier dealers <br />or do a search online <br /><br />Rich

 

[Wellcraft 89]

Re: 4.3L Mercruiser starting problem

Try to support here first then try this place www.mercrusierparts.com <br /><br />Rich

 

[lorax]

Re: 4.3L Mercruiser starting problem

My '89 4.3L has the same problem only intermittent. The parts counter guy, who I have great faith in, told me that it's a Mercarb and somebody on this forum said that those carbs are pretty cheesy units and prown to flooding on shutdown. He indicated that Mercury offers a kit of some kind for correcting the problem.

 

[svenster2]

Re: 4.3L Mercruiser starting problem

What if it is hard to crank after running for a while?

 

[ufm82]

Re: 4.3L Mercruiser starting problem

jb71- <br /> First thing you should check is your fuel tank vent line. The thru-hull fitting plugs up with spider webs or bugs , etc. and causes a vacuum lock in the tank. The boat will act just like you are describing. Do check the carb and see if fuel is squirting out when you move the throttle linkage. Chances are it isn't. That would explain the shut-down at idle. It also explains the delayed restart. When the motor is running at speed, the draw from the fuel pump is sufficient to overcone the vacuum. BUT, at idle, when the pump isn't pulling as much, the vacuum overcomes the draw and prevents fuel flow. Then, when you are trying to restart, the fuel pump is hardly drawing at all. <br /><br />The vent may be plugged, but they usually aren't 100% plugged. As the boat sits, the vacuum is gradually relieved as the vent tries to do its job. Check that vent fitting and clean it out. Also make sure your vent line from the tank to the fitting isn't kinked or full of water/fuel.<br /><br /> The easiest way to diagnose this problem is to unscrew your filler cap after it does it. If you hear it suck air in as you unscrew the cap, I guarantee that a vacuum lock is your problem. A 14 year old boat sure is a suspect for a plugged vent.<br /><br />UFM82

 

[jb71]

Re: 4.3L Mercruiser starting problem

UFM82,<br /><br />That is some great info if it is, in fact, the problem. What is interesting is that a day or so after I last took it out (ended up getting a tow back to the dock!!) I was walking around the boat and noticed gas dripping out of the vent line at a pretty good rate (making a nice little stain on the boat!). Anyway, I assumed the gas in the tank had expanded because of the heat of the day and was overflowing out the vent line...I opened the filler cap and there was a great sucking sound. I will definitely check the vent line.<br /><br />The only thing that has me doubting whether or not this is the problem is the fact that my friend did tell me that he observed fuel shooting out when I worked the throttle while the boat was off, so I don't know???? What do you think?<br /><br />Thanks<br />Jeff

 

[ufm82]

Re: 4.3L Mercruiser starting problem

There shouldn't be any fuel getting out of the vent line- it rises from the tank and then drops down to the vent- if fuel is in the line, it blocks off the ability for fumes to escape- that leads to a build-up of fumes in the bilge area and then BOOM- your boat goes up like a bomb. <br /><br /> Make sure the line isn't blocked or sagging. Another indicator of a blocked vent line is fuel spitting back at you when you fill the tank. It should vent through the fitting, not back through the neck. <br /><br /> If you saw fuel in the carb, it may not be the problem. BUT, I would check that anyway just to eliminate that possibility. <br /><br />UFM82

 

[jb71]

Re: 4.3L Mercruiser starting problem

Thanks, I will definitely check out the vent line and make sure it is all clear.

 

[loadnet]

Re: 4.3L Mercruiser starting problem

Before you buy a rebuild kit you may want to just take the carb apart a bit and see if the float chamber is full of fuel to the very top, and the float is possibly stuck in the UP position, or has a hole in it or maybe the needle is stuck open (OUT)<br /><br />If you are out in the boat when this happens...try tapping on the carb bowl lightly to see if the float will UN-stick enough for you to get the boat home..<br /><br />When you pull the carb apart....<br /><br />Look inside the carb float bowl closely to see if it's stuck in the UP position or for fuel over the TOP of the float.<br /><br />CLEAN the needle and seat that is located just under the float..to make sure it's moving freely OUT and BACK IN when the float is lifted up and down being careful not to bend the seat/tab that regulates the amount of movement the needle travels inward and outward.<br /><br />You can also..... slide the pin out of the tab under the float ball and remove the float entirely, then stick it in a container of gasoline like for 20 minutes or so to see if it SINKS..<br /><br />If it SINKS it has a hole in it.. and must be replaced.<br /><br />If the needle that shuts off the gas is sticking open (OUT) the float bowl chamber will OVERFILL and you'll have what they call a 'leak down' after you shut the engine down.<br /><br />which is what I think is wrong with your boat right now....meaning,<br /><br />..excess fuel in the float bowl chamber ABOVE the float and in the gas feed line leaks out the overflow tube right into the carb intake chamber running down into the cylinders that had intake valves OPEN at the second you shut down the engine, thus flooding those cylinders with fuel.<br /><br />If you are on the water at the time....<br /><br />After waiting a good period of time for the funes to get outa there (Lever in WOT) you MAY be able to start the engine however it WILL crank real hard when first turning it over but eventually crank faster as the gas escapes out the exhaust little by little.<br /><br />BACKFIRES are common when starting a boat up after a leakdown because of all that excess fuel sitting on top of the pistons.. so this is not something you want to kinda just let go till next weekend unless you have a remote control starter mechanism allowing you to swim at least 1/4 mile away from the boat prior to hitting the auto-start button. <br /><br />and pay close attention to the info on the tank vent cuz that guy is 200 percent correct on his statements.<br /><br />Good luck to you, I hope you solve the problem soon!

 

[jb71]

Re: 4.3L Mercruiser starting problem

What you described is what seems to be happening. Thanks for all the helpful info...I have called to check on a gasket kit and plan to pull the carb apart (with fingers crossed) in the next week or so (when I get some time off). I am a novice at all this but with you guys' info I will hopefully, be up and boating again in no time.<br /><br />I am just hoping it stays warm long enough for me get in some more wakeboarding.<br /><br />Thanks again.<br /><br />Jeff