trouble starting 1996 4.3 mercruiser... will only start with starting fluid and run

[adg72484]

I am trying to get the boat ready for the season and am chasing problems that started last season.
A little history on the boat, I bought it as a fix-it project and ended up putting a rebuilt engine into it because
of a cracked block. I got it running last season but not without issues.

With the rebuilt engine, new fuel pump, filters, I had trouble getting the boat started. I use starting fluid sparingly and it will start and run everytime. If I shut the boat off after running for a little while it will not want to start. Again if i give it a shot of starting fluid it starts right back up. I have checked the timing several times and it is set to factory spec. I installed a new choke motor and think I have it adjusted correctly. At cold start the choke plate is completely shut and slowly opens to wide up as the engine warms up. Still won't start without help from starting fluid. I know I shouldn't have to use starting fluid to get it started so looking for any ideas what else to check.

The boat is a 1996 vip 4.3 mercruiser with the 2bl carb. I also had it on the water once last season and it would start with a shot of starting fluid and idled but it would not run in gear at idle. At higher RPM it would run in the water but didn't feel like it had a lot of power.

Any help would be appreciated... I'm thinking its a carb issue but not real strong in that area.

 

[Don S]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Does the fuel pump run? It's electric.

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Does the fuel pump run? It's electric.

Yes its brand new. The boat will run decent without a load after the initial shot of starting fluid. Once started it will stay running
at idle or any other RPM until I shut it off. Then it wont restart. It will also run in gear (without load) Sometimes If I crank it for an extended amount of time it will restart without the starting fluid but it takes 20+ seconds of cranking.

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

How old is the fuel?

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

I removed most of the old fuel in the tank when I replaced the engine. I then filled it full with fresh fuel last season. I topped it off at the end of the season and added a stabilizer to the fuel.

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

I removed most of the old fuel in the tank when I replaced the engine. I then filled it full with fresh fuel last season. I topped it off at the end of the season and added a stabilizer to the fuel.

"Should" be ok, but still sounds like a bad fuel problem. Can you hook up a remote tank with really fresh fuel and see if it starts ok?

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

"Should" be ok, but still sounds like a bad fuel problem. Can you hook up a remote tank with really fresh fuel and see if it starts ok?

Hmmm, what would be the easiest way to try that? I don't have a remote tank.. Would it work to remove the fuel supply hose from the tank and stick it in a gas can full of fresh fuel? How long do you think it would take to run the old fuel out of the filter/lines to where I would be sucking fresh fuel? I would have to get it started using starter fluid to run and burn off the old fuel in the filter/lines

 

[thumpar]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Check to make sure you get voltage for the fuel pump while cranking. Normally the fuel pump works when you have oil pressure or while cranking only. It could be that it is not getting the voltage while cranking and only once started because of the oil pressure.

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Well, I'm not going to recommend using open cans and loose hoses - that's up to you. Correct way would be to connect a (clean) remote tank directly to the suction side of the pump. This would reduce the amount of old gas to be burnt off. As you say, you would have to start the engine with starter fluid, then let it run for 5 minutes say? Then let it cool, and try again. Can you borrow a tank?

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

It does have voltage during cranking. I did notice that it will shift into forward gear with no load but dies everytime going into reverse with no load. Also should the gas inside the carb being dribbling in or should it be a nice mist?

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Also should the gas inside the carb being dribbling in or should it be a nice mist?

It should be a mist. If you're seeing raw fuel after the choke plate has opened, then it may be a carb problem. Did the rebuilt engine come with a rebuilt carb, or did you use the carb from the old engine?

 

[dubs283]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Also should the gas inside the carb being dribbling in or should it be a nice mist?

at idle you should see no fuel dripping or spraying down the carb throat - was the carb rebuilt recently??

did you install all new tune-up parts and fuel filters after you got rid of all the old fuel??

have you checked fuel pump pressure and vacuum??

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

It should be a mist. If you're seeing raw fuel after the choke plate has opened, then it may be a carb problem. Did the rebuilt engine come with a rebuilt carb, or did you use the carb from the old engine?

I reused the old carb. It is definitely not a mist after the carb plate opens.. I look down in there and its dribbling drops of fuel into both barrels. What would be the fix for this?

 

[dubs283]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

What would be the fix for this?

rebuild the carb

have you checked/set the igniton timing??

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

I reused the old carb. It is definitely not a mist after the carb plate opens.. I look down in there and its dribbling drops of fuel into both barrels. What would be the fix for this?

Something definitely wrong with the carb. Maybe time for a rebuild kit!

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

rebuild the carb

have you checked/set the igniton timing??

I set it last season to factory spec. Could you refresh me where it should be and how to put it into the base ignition mode needed for setting it? I have a timing light so I can recheck it. So at idle with an open choke plate the fuel should be a mist not droplets? Is the carb rebuild pretty straight forward or should I have a local marina do it?

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

Is the carb rebuild pretty straight forward or should I have a local marina do it?

That depends on your skill level. It will be cheaper to do it yourself but you will need a good manual! If you're not sure, then have a professional do it.

 

[adg72484]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

That depends on your skill level. It will be cheaper to do it yourself but you will need a good manual! If you're not sure, then have a professional do it.

I can handle it i'm sure but can you recommend a good kit that will have everything I need? The carb # is an 807764 date code 6102.

 

[Another retired guy]

Re: trouble starting 1996 4.3 mercruiser... will only start with starting fluid and r

That's a Holley 80776?? Lots of places online offering rebuild kits but, sorry, I have never had to buy one so can't comment. Just pick one and go with it