Merc 4.3 Keeps stalling

Finially convinced a buddy to join the boating world. We tested a boat out and bought it. NOw that we have done some play with it on the water , a problem has developed. The boat keeps stalling in the lower rpm stages. You can be going at a steady slow speed and it will just die, or any sudden change in throttle position will cause it to stall. Exhaust showes no smoke, so not flooding right. I suspect the boat needs a proper water seperator, and a faulty fuel pump. Would it not stall at high rpm if fuel pump was bad. Appears it now has an automotive in-line filter now.Anything else to look at on carberator? It seems to start best with no extra throttle, just in nutral, but will often die before underway again. It is a '90 4.3 v-6 carberated? Help!

Re: Merc 4.3 Keeps stalling

Tell it that it is time to quit stalling and give you an answer!

When was the last time it had a full tuneup?

Re: Merc 4.3 Keeps stalling

I have an '89 4.3L Merc that had a similar problem. I had the carb rebuilt and has worked great since.

Re: Merc 4.3 Keeps stalling

Yes that is one of the answers the shop gave too, along with some sensor that works along side the throttle cables . The rebuild for carb was quoted @$400 and sensor was a five hour job! Either one is not cheap, but neither is a starter if this goes on much longer. Another problem that came with this boat is the trim guage does not work. Wires are all good, but could someone explain the tilt sensors on port and star' sides of the leg? Are these just limit switches, or do they send a signal to the guage too. Guess my buddy should buy a manual, but not a crapy one. Who makes a good one, hard to tell when they are all sealed up until you buy them.

Re: Merc 4.3 Keeps stalling

along with some sensor that works along side the throttle cables

and sensor was a five hour job!

Click to expand...

I would be finding out what sensor that is, because I know of no sensor by the throttle cables, let alone one that takes 5 hours to repair.

The only good manual is the OEM. Might give Ebay a check, he needs Mercruiser service manual #7 for the engine. He also needs sevice manual #6 for the outdrive, transomshield, and trim systems. That one is online, at this link.
http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf