Need help with a 4.3 v-6
 

Ok, I own 98 Glastron with a 4.3. Aprox 200 hrs. The boat runs perfect on smooth water but as soon as it gets a litte rough the motor cuts out. It sounds as if it is backfireing through the carb. I can be on smooth water running great then turn the wheel back and fourth pretty harshly and that will also cause it to cut out. I have changed plugs, wires, filters and checked the cap. It sounds like there is a short somewhere. Any help on where to start checking would be great. I need to get this prob fixed because my wife has agreed to upgrade to a bigger boat this winter.:D :D :D :D

almost sounds to me liek the floats in the carb are off. Unless im way off and this is an EFI! If you think its electrical try starting the motor up at the dock and going to the back and wiggling the wires around....you may find the sort that way.....it there is any electrical gremlins they seam to be mostly around the plug from the harness to the engine....you may have some corrosion or just a loose plug.. :D

at only 200 hours??
The 4.3 we have in the Baja has around 1300-1400+ hours (1990) Im not sure on how hard the first 7 years were on the engine (known they were over 100hours tho) but i know that these last few years have been driven to death (not dead yet :( I frown because i want it dead so i can put a 350sbin it.)

Wally, it is a two barrel carb. I will hook it to the hose and start wiggling:D :D Hyperbaja, man thats a ton of hours, I new these were good motors!!! Mine really does run good. I have never put a GPS to it but the speedo hits about 58 with one person. It gets pretty wild because it is only a 17.5 ft boat.

HERE'S THE PROBLEM--->>>>"Ok, I own 98 Glastron with a 4.3"

:D :D :p

In a year or so, you just might be saying that to me, so I had to do it first!!


heheheehehe :p

I knew it was just a matter of time before you would show up!:D :D If I cant figure anything out on this then I am going to have to bribe you with a few beers to help me out!!

It will take more than a few beers to get me to pull that motor and burn that boat....hehehehe

don't forget to check wiring up around
the dash, connector plugs, "kill switch".
when this happens, do your gauges
flicker ?, if so, it's definetly electrical,
do like wally said, and start shaking
wires, and see if you can "recreate"
the problem.
hope this helps
jt

let us know what you find :confused:

Loose wires killing the ignition doesn't usually cause a backfire through the carb. My first place to look would be the float.

Goforbroke, when I am checking the float, what exactly would I be checking for. I know when the floats get stuck what a motor will do but this is not the case. Is this an adjustment that I need to check?

When it acts up try putting a jumper from the battery + to the coil + and if that clears it up you have a open somewhere,also keeping a eye on the gauges is good advice. The shift interupt switch may also cause a miss fire if it's out of adjustment.

the "backfire" is caused by an irratic
or untimed spark, due to random ignition
interruptions, if it was fuel (lean condition)
related, it wouldn't care if it was rough
or smooth out.
yes , check shift interrupt circuit also.
bypass wire to coil will also eliminate
wiring system problems.
good luck.

JTB, yes its a measurement you are checking. You measure its open and closed position. You will need to find the spec for the carb. Also check to see that it moves smoothly through its range and that the needle and seat move properly too.
jt29olhp500s- erratic spark could cause that but its rare and should also backfire through the exhaust if its that random.

It is also possible you have water in the bottem of your fuel tank that is below the fuel pick up-until you bounce it around.
Good Luck!

Is there an additive that you know of that would take any water out of the tank or is draining the only solution??

If your going to start shaking wires, especialy plug wires, please put a good heavy rubber glove on. Been there.....zap

First use a water level finder paste on a stick/dowel to be sure you have water,then suck it out with a hand vacum type oil changer thru the removed pickup tube.Try to raise the bow so all the water will run aft toward the pickup,follow up the job with a qt. of MDR "Water Zorb".