1994 4.3 mercruiser problems

[dinges]

My husband and I recently purchased a 1994 Chaparral which has a 4.3 liter Mercruiser engine. We have taken it out twice since we bought it and each time it begins to sputter, backfire and acts like it is starving for fuel. The first time it happened, he changed the fuel filter and put more gas. We figured this fixed the problem and took it out yesterday. Well, it didn't help. It will run ok and then it will start to sputter again. Do you have any suggestions?

 

[Haut Medoc]

Re: 1994 4.3 mercruiser problems

Do you have a water separating fuel filter?

 

[hoot]

Re: 1994 4.3 mercruiser problems

it's good to see another from north alabama found this great forum. good ol' tennessee river boater. watch for floating trees!! if you will read thru the postings, you will see lots of topics similar to yours and suggestions. how long since a full tune up on the boat? how long does it run before the problem occurs? how mechanically inclinded are you or the husband? some basic trouble shooting is necessary. could be anything from water in fuel, stopped up vent line, timing not advancing, ignition parts getting hot and failing,carb needs rebuilding,... two easy things you can do when it gives trouble is stop the engine, pull the carb 'air cleaner', hit the throttle, and see if any gas squirts into the carb. pull a spark plug wire, hold the end close to the end of the plug, and start motor. watch for a strong spark. this will isolate the problem to either fuel or spark.

 

[dinges]

Re: 1994 4.3 mercruiser problems

Yesterday, it ran for about 30 minutes and we were able to pull a 110 pound skier before we had any problems. Beyond that we could only run the engine for mere minutes at a time. My husband is mechanically inclined, but has never worked on a boat (mostly cars), and we are actually getting ready to go work on the boat. He read your responses and seems to know exactly what you are talking about, but please keep the info coming. Thanks!

 

[dinges]

Re: 1994 4.3 mercruiser problems

are there two different filters on the boat? one for the water/fuel seperation and one just for fuel?

 

[vipzach]

Re: 1994 4.3 mercruiser problems

Originally posted by tnadinges:<br /> are there two different filters on the boat? one for the water/fuel seperation and one just for fuel?

The water seperator will look like an oil filter. Usually inline before the fuel pump. The gas comes through it and if water is present it will seperate it out of the water and filter out dirt and things. Most boats will also have a filter directly in the carb inlet.

 

[hoot]

Re: 1994 4.3 mercruiser problems

in a lot of cases, heat builds up and affects igniton components. after the motor cools off, the motor will run fine until it heats up again. ignition components range from simple points & condensor to electronic sealed items. backfiring or just missing or surging? backfiring can be a sign of lack of fuel or timing not right or distributor problems. you have to be patient and not get discouraged with the boat. it takes time to sort thru this stuff.

 

[dinges]

Re: 1994 4.3 mercruiser problems

Well, thank you for all of your responses! We found that it was a clogged fuel line and we were able to fix it with no problem! We spent all weekend on our boat and had a rockin' time! Happy 4th!