4.3l mercruiser does not start

[bigjohnp]

I have a 4.3L mercruiser that starts and runs at idle speeds but when I give it any throttle it dies.

Got boat off trailer and idled around cove waiting for wife and son, when they got on idled out of no wake zone, gave it throttle and it sputtered then died. Got it started again and same thing. sometimes does not start, kept trying and it would start. Finally idled around for 3-4 min and it died and will not start, it just sounds like something spinning when I turn the key. Sound is similar to hydraulic sound, I know it is not hydraulic just trying to tell you the sound it makes. Got towed to ramp, tried it one last time and still just the drill spinning sound, the engine is not trying to turn over.

It is a 1998 Mercruiser 4.3 L with thunderbolt ignition model MCM4.3 Litre
engine serial number 0L048359

One last thought. The boat just had the stringers and floor replaced, and this is my first time back out. Could something be disconnected?

Thanks for your help,

John

 

[Wotknot]

Re: 4.3l mercruiser does not start

I have a 4.3L mercruiser that starts and runs at idle speeds but when I give it any throttle it dies.

Got boat off trailer and idled around cove waiting for wife and son, when they got on idled out of no wake zone, gave it throttle and it sputtered then died. Got it started again and same thing. sometimes does not start, kept trying and it would start. Finally idled around for 3-4 min and it died and will not start, it just sounds like something spinning when I turn the key. Sound is similar to hydraulic sound, I know it is not hydraulic just trying to tell you the sound it makes. Got towed to ramp, tried it one last time and still just the drill spinning sound, the engine is not trying to turn over.

It is a 1998 Mercruiser 4.3 L with thunderbolt ignition model MCM4.3 Litre
engine serial number 0L048359

One last thought. The boat just had the stringers and floor replaced, and this is my first time back out. Could something be disconnected?

Thanks for your help,

John

From what you said, sounds to me like you've got 2........maybe 3 issues. The "spinning" you're hearing is probably the starter solenoid not engaging therefore the starter isn't engaging the flywheel. You said the stringers just got replaced, was the engine realigned when it was set back in? On the no-go issue, how was it running before the work was done? How long was it in the shop between uses? Could just need a basic tuneup, or water in the tank/carburetor, etc. One of the pros will get around to here eventually and give ya some more help. btw, welcome to the board.

 

[Limited-Time]

Re: 4.3l mercruiser does not start

Sounds like the bendex (sp) on the starter is not kicking in, the spinning sound is the starter turning. As for the no go sounds like the accelerator pump in the carb is bad.

 

[bigjohnp]

Re: 4.3l mercruiser does not start

Thanks for some fast replys.

The engine was not taken out for the stringer replacement.

I just bought the boat in May. The first 4 weekends the boat ran great. It has been 3 weekends since I have had the boat out on the water.

The hour meter says 128 hours, I bought it with 112 hours. based on the floor and stringer issues I had, i am assuming there was very little maint. done to the boat.

Also today the key was hard to get to engage. I had to hold the key and the back of the ignition on the dash and giggle the key to get it to try to start. After I got it started finally when unloading off the trailer it seemed fine. When I was messing with it in the lake 1 out of 6 times I had to wiggle it around again to make it try to start.

Thanks again

John

 

[dodgeramsst2003]

Re: 4.3l mercruiser does not start

Agree with limited-time, sounds like your accelerate pump is not working properly. I had a boat once that acted the same way you describe. One way to check if you want to take it out again ( not advisable just a suggestion) is to ease into the throttle very slowly. When I say very slowly I mean slower than the slowski's from comcast commercials if you have them there. if it eventually runs and runs fine once at speed then you know the accelerator pump is not working. You might pull the carb, and see if the spring and ball are stuck, gunked up, or whatever.

 

[baylinerbill]

Re: 4.3l mercruiser does not start

sounds like a carb issue similar to what i had on my 97 4.3 merc. i would have it rebuilt or rebuild it yourself if you are capable. If its a new boat to you, I would do all the basic tune up stuff now. Never trust a previous owner. Fix you wires also. You should never have to giggle anything electrical, that means there is not a solid connection.

 

[bamadave]

Re: 4.3l mercruiser does not start

John
1 weak battery, that is way the starter is spinning but not turning the engine over. Charge battery and do a load test, if it fails the load test, replace.

2 Sounds like the ignition switch might be loose in dash? If switch moves around, tighten the nut on the switch. If the switch is tight and you have to wiggle to make switch work, check connections on the back of switch. If suspect, repair or replace as needed.

3 Stalling when accelerating, how long since a tune up? Does it stall when you idle up in neutral, or in gear only, or both?

 

[bigjohnp]

Re: 4.3l mercruiser does not start

no idea when it was tuned up last.

it always stalls when engaging into gear, sometimes i can idle slowly maybe a little faster then it dies. If I barely leave it engaged just past no wake idle speed it will try to die then surge then try to die, after 3 or 4 times it will die. If I try to go faster it will die. If when it surges and tries to die I throttle back it will stay in idle and not die. But when I tried to idle back to the ramp I made it most of way and then it died, would not restart, then it led to the spinning sound.

So I'm down to charge and test battery, replace if fails.

tighten ignition switch and connections

carb rebuild

replace accelerator pump

Stabil in gas tank

tune up

anything else?

thanks again for all the quick replies!

John

 

[Bondo]

Re: 4.3l mercruiser does not start

anything else?

Ayuh,... If it isn't Cured when you get done with your List of things to Do,.....

Change out the Lower Shift Cable,.... It sounds like your's is Sticking....

 

[bigjohnp]

Re: 4.3l mercruiser does not start

is the lower shift cable a quick change out?

 

[Don S]

Re: 4.3l mercruiser does not start

is the lower shift cable a quick change out?

They have been called many things, but NEVER a quick and/or easy job.

 

[droland]

Re: 4.3l mercruiser does not start

You might also check the fly wheel for missing teeth regarding the starting noise. I had that same issue, replaced the starter & selanoid, and the problem persisted so pulled it back off and was able to see the fly wheel with a chunk broken off it.

 

[bigjohnp]

Re: 4.3l mercruiser does not start

I have never rebuilt a carb before, I have worked on one on my 4 wheeler though. Is there anywhere online or perhaps here that will tell me step by step how to rebuild a carb?

I have taken it off, do I order a rebuild kit and swap pieces or what??

Thanks,

John

 

[imported_TheMan]

Re: 4.3l mercruiser does not start

There are many manuals that tell you how to rebuild the carburetor. If you are patient and detailed enough to follow directions to the letter, you can do it yourself. It is NOT hard work, just detailed.

Find yourself a factory service manual.. I'm not sure of the years covered in the linked manual, but I believe the carburetor section is pretty identical regardless of years... But I'm sure someone will correct me if I'm wrong
http://www.boatfix.com/merc/Servmanl/18/18covr2.pdf

And yes, you can order a carburetor rebuild kit that will include a new needle, ,seat, gaskets, accelerator pump, etc.

One other minor detail to add to the list just to be certain.. Make sure your choke is operating correctly..

 

[bigjohnp]

Re: 4.3l mercruiser does not start

Finally got back to the boat. I have rebuilt carb, replaced fuel filter/separator, bought new battery.

Went to try and start and it just sounds like a vacuum cleaner motor when I turn the key????

What should be my next step?

replace starter? solenoid? ignition?

Thanks,

John

 

[bigjohnp]

Re: 4.3l mercruiser does not start

if I do need to replace the starter should I go with OEM or is aftermarket good?

 

[mthieme]

Re: 4.3l mercruiser does not start

Aftermarket is okay, just mark sure it is a marine starter.
ARCO handles rebuilt marine starters.

 

[thunked]

Re: 4.3l mercruiser does not start

I have the same engine in a 1991 Capri 4.3L Mercruiser.

At the end of the throtle cable there is a little switch that helps kill the idle when putting in gear. The issue with mine was once I gave it any gas it wouldn't start again. I had to remove that switch/adjust the cable to get it started. Look where the cable connects to the housing see if yours is jammed.

Once I unjammed mine I started getting issues similar to yours. I can start the boat right up, runs excellent out of the water, but as soon as I put load on the prop it dies right away.

I am certain my carb needs to be repaired as gas splashes out of it. I think it's sucking air through a gasket and that's why it's dying.

Anyone know the best/cheapest place to buy carb rebuild kits online? Thanks

 

[Bondo]

Re: 4.3l mercruiser does not start

August 12th, 2008, 11:53 PM

Ayuh,... I think ya gotta start a thread of your own Thunked,....This 1 is over a year old....
Once you Do,.... We'll get into the Multipule Problems you have...
Make sure to tell Us which Carb....

 

[Don S]

Re: 4.3l mercruiser does not start

Welcome to iboats.
Please, read the archives and learn from them, but please, DO NOT post to them.
If you have a question, it's best to start a new thread of your own. Don't just jump in on the end of an old post of someone else's.
It will only take a couple of replies to your question and it will no longer be seen and everyone will be answering the original posters question ....... again.