4.3 Liter V-6 problems

wakeloose · Newbie Joined: 22 Jun 2004 Posts: 6

Just wanted to share. I have been reading some of the problems with this motor and have been experiencing much of the same, cutting out, and dieseling. Mine got so bad that after about 3400 rpms, the engine would backfire. The plug wires had been changed but the wire from the coil to the distributor cap had not. I changed this wire and the engine now runs like new. I'm surprised that it was that easy of a fix...

D-GOOSE · Addict Joined: 09 Aug 2004 Posts: 750 City: Antelope

Ya all it takes is one wire to go bad and pow you have a problem. Surprised

Have you had the motor die out at high rpms but will restart again and run fine at lower rpms?

Leggester · Posted: Aug 24, 2004 5:40 am Post subject:

Haven't had any problems with mine in 8 seasons.

The ONLY thing that was "bad" was after the break in. Had to bump the idle RPMs by about 100.

Brit Rider · Posted: Aug 24, 2004 12:05 pm Post subject:

we use the mercruiser 4.3 V6 and it runs on after shutting it down.. for upto 10 second sometimes.. seems like a bit of a safety issue and its a pain in the ass! no one has been able to solve the problem yet - anyone has this problem too?

MadDog · Soul Rider Joined: 13 Jan 2003 Posts: 465 City: Upstate NY

we have the same motor in our boat. I had the same run on issue last year, but found that my idle was set too high. Lowered the idle back down, and it solved the problem.

Brit Rider · Posted: Aug 24, 2004 1:49 pm Post subject:

my idle seems very low, i don't dare set it lower or i think i'll have troube with it.

any other ideas? asre you sure it was just the idle? if ti was i might jsut adjust it a tiny it and see what happens

Leggester · Posted: Aug 24, 2004 2:31 pm Post subject:

I'd say around 600 rpm.

Plus, timing belts stretch a bit. I'd check the timing too. Piece of cake.

Brit Rider · Posted: Aug 25, 2004 3:14 am Post subject:

we had the timing adjusted already.. and it was suggested that it may be a faulty thermostat (engine was so hot the fuel was still burning or something).

It idles ad like 700... so maybe we'l check that. Thanks Leggester,

KristianB · Posted: Aug 25, 2004 3:31 am Post subject:

Description of the problem at Sometimes when you turn the key off the engine keeps running

And try http://marinemechanic.com/site/page154.html which seemed a bit more fix oriented...

/K

wakeloose · Newbie Joined: 22 Jun 2004 Posts: 6

Those engines have timing belts? I thought they were timing chains...

Brit Rider · Posted: Aug 25, 2004 5:29 am Post subject:

KristianB, Thanks man, I'm gonna give someof thos eideas a try.

We already did new plugs, timing so I'll try rurning down the idling RPM a little.
I'm guessing to do this i jsut adjust the throttle cable ont he throttle body? do i just let it out a tiny bit?

gmarkham1 · Addict Joined: 10 Sep 2003 Posts: 505 City: janesville

All you need to do is adjust the idle screw. which is located near where the throttle cable is attached to the motor.... just follow the arrow(i have perfect pass installed which is why it doesnt look exactly the same.

Turning down the idle worked for me, also try premium, or just a different gas station... stay away from kwik trips, try for good reputable places like amoco, mobil, or bp, and let the engine idle back down for a minute, all these things have helped me

riverfreak · Posted: Aug 25, 2004 11:13 am Post subject:

I run nothing but super in mine - give it a few seconds before just killing it - it will help the running on - as far as the missing or cutting out - alot of times its gas - I use gas treatment when ours starts that - it always helps.....

but yes, there have been a lot of complaints about the 4.3 V6 but a friend of mine has the 3.0 and it does the same thing

Brit Rider · Posted: Aug 25, 2004 11:25 am Post subject:

right i'll hook up the hose on the outdrive tommorrow and have a tweak.

Thanks Guys - and sorry for the Hi-jack

MrBlean · Posted: Aug 25, 2004 1:20 pm Post subject:

Mike - as the url and others have said, dieseling is often caused by carbon deposits on top of the pistons staying real hot and igniting the fuel. They can get there through the engine running a tad rich and/or the use of poor quailty (supermarket) fuel.

Try running the boat on Shell Optimax, the BP equivalent or Texaco fuel. These all have more and better additives in them to keep your engine clean.

If you have a diesel car, use Shell or Texaco fuel. The sulphur in diesel fuel acts as a lubricant for the fuel pump and since the advent of ultra-low sulphur fuels, diesel has become less "slippery". Only Shell and Texaco add lubricity enhancers to their diesel fuel to compensate.

Supermarket fuel may be cheaper (except Tesco's diesel which is often more expensive!) but in the long run it takes it's toll on your fuel pump which can be a costly replacement. That only applies to diesels, of course.

Brit Rider · Posted: Aug 25, 2004 1:53 pm Post subject:

Well the only gas station we use is about 600 yars from where the boat is and 30 yards fromt he slipway. its a "total" station.

Interesting you should mention other fules, we re filled at a bp ont he way into windermere a few weeks ago and then kept it topped up with texaco on the lake.. it didn't run on quite so much.. i'm pretty sure. but it could have been coincidence

Not sure i can be bothered to refill 30 miles out of our way though just to stop it running on.. but i'd like to have it fixed before we sell it....

MrBlean · Posted: Aug 25, 2004 11:57 pm Post subject:

Mike - Make your next boat an EFI - you'll never have the problem in future

Is your boat moored at Windermere and do you fill up at a Marina? If so, and I'm just curious on this as our boat is still on petrol but is there any LPG available at the marinas there?

Whats the price of fuel at the Marinas? I know that in the US they often pay quite a premium for a lakeside fill up.

Unfortunately, we have to cart all our fuel in Jerry Cans. There's a fuel station a mile away so we fill the cans en route. I once filled the boat en route and the resulting wake was enormous. Who needs water-filled fat sacs when you have a tank full of fuel right at the back of the boat Exclamation

Best excuse I know for riding first (whilst it's still full) Laughing

Brit Rider · Posted: Aug 26, 2004 1:39 am Post subject:

Its £1.00 per litre so not cheap at all Shocked

Nope boats back outside my house now, ready to return to its home in wales this weekend.

MrBlean · Posted: Aug 26, 2004 1:56 am Post subject:

Mine's on the driveway too. Took it out to fit a heater, tower and clean it and whilst it's out, we suffer a toxic blue-green algae bloom at the lake and are banned from using for the foreseeable future until the bloom clears Crying or Very sad

Even with treatment it takes weeks, apparently so we may get a week or two of riding at the back end of the season.

At least it's been windy and, living right by the beach, I've been able to go windsurfing instead.