Merc 140 Fuel pump and other stuff

[m*a*baity]

I'm back fellas. my first time ever on the water this past weekend almost left me stranded and the bad thing is I forgot my paddle at home. Got it fired back up and high tailed it to the ramp. Have my cosmetics finished up on my boat now its time to concentrate on the engine. Boat has been sitting for 2-3 years and been ran maybe an hour total. I did get a good 1-2 hours out of it this weekend before it wouldn't fire back up. The lake is a lonely place when it gets dark. Fires up and runs every time on land with the muffs hooked up. Doesn't want to idle in the water.

I'm thinking I need to start with fuel pump, new fuel lines and carb rebuild. I have already replaced the starter, alternator, and spark plugs.

I guess my question is, can I use an automotive fuel pump? If so what year, make and model do I tell them at Advance? Also, distributor cap, and rotary button will be changed next.

I'm working on a 1981 Caravelle. Mercruiser 140. I have the manual downloaded, so I can get directions there.

Final question. How much of a pain is it to replace the exhaust/intake manifold gasket. I'm have a trickle of water, and an exhaust type noise coming out of it. Thanks for all your help, you guys have saved me a ton of money already. I'm not quite shade tree, but I'm not scared to turn a wrench either. Thanks, Mark

Will post some pictures of my upholstery work later. Thanks

 

[Haut Medoc]

Re: Merc 140 Fuel pump and other stuff

I'm back fellas. my first time ever on the water this past weekend almost left me stranded and the bad thing is I forgot my paddle at home. Got it fired back up and high tailed it to the ramp. Have my cosmetics finished up on my boat now its time to concentrate on the engine. Boat has been sitting for 2-3 years and been ran maybe an hour total. I did get a good 1-2 hours out of it this weekend before it wouldn't fire back up. The lake is a lonely place when it gets dark. Fires up and runs every time on land with the muffs hooked up. Doesn't want to idle in the water.

I'm thinking I need to start with fuel pump, new fuel lines and carb rebuild. I have already replaced the starter, alternator, and spark plugs.

I guess my question is, can I use an automotive fuel pump? If so what year, make and model do I tell them at Advance? Also, distributor cap, and rotary button will be changed next.

I'm working on a 1981 Caravelle. Mercruiser 140. I have the manual downloaded, so I can get directions there.

Final question. How much of a pain is it to replace the exhaust/intake manifold gasket. I'm have a trickle of water, and an exhaust type noise coming out of it. Thanks for all your help, you guys have saved me a ton of money already. I'm not quite shade tree, but I'm not scared to turn a wrench either. Thanks, Mark

Will post some pictures of my upholstery work later. Thanks

YOU MUST USE A MARINE FUEL PUMP, NO EXCEPTIONS!.....
I would change the water separating fuel filter first, if you have one...
If you do not, I would get a five gallon aux tank, fill it with fresh gas, temp. plumb it into your fuel system & see if it clears up your idle in water troubles....
It sounds like you have a water in fuel problem....
You may need to completely drain your tank & add a water separating fuel filter.....
What I'm saying is: Don't start throwing parts at it, diagnose it first & proceed from there.....

 

[havasuboatman]

Re: Merc 140 Fuel pump and other stuff

I highly recommend that you DO use a marine fuel pump. The marine mechanical fuel pump has an extra hose fitting that runs up to your carb. this fitting does absolutely nothing, unless the diaphram fails. then it keeps fuel from leaking into your bilge averting a possible explosive fire.
The intake/exhaust is no big deal. Make sure you get all of the mating surfaces all cleaned up. A friend may come in handy for reassembly, though.

 

[Scorpion168]

Re: Merc 140 Fuel pump and other stuff

I'm very interested in this post - because I'm having the same problem. My '84 140 Merc runs like a champ in the driveway - but dies as soon as I move out of neutral on the water. I did the air-in-the-fuel test, and there was no bubbles. My next test is the vacuum test - I still have to buy the gauge. Someone else told me the pump may be inadequate under a load (in gear in water). Thoughts??

 

[m*a*baity]

Re: Merc 140 Fuel pump and other stuff

I'm very interested in this post - because I'm having the same problem. My '84 140 Merc runs like a champ in the driveway - but dies as soon as I move out of neutral on the water. I did the air-in-the-fuel test, and there was no bubbles. My next test is the vacuum test - I still have to buy the gauge. Someone else told me the pump may be inadequate under a load (in gear in water). Thoughts??

Mine is opposite of yours. Won't idle in water, doesn't run like a champ anytime. No hole shot at all it bogs if I give it instant throttle and slowly creeps up to speed. Gonna replace the manifold gasket first because it is leaking water on the outside and might be leaking into the intake. See how that goes. That might be my problem, it just runs rough kind of like a broke vaccum line in an old 350 chevy motor. Have had that in the past. Good luck with your problem!

 

[GOHAWKS#1]

Re: Merc 140 Fuel pump and other stuff

I'm back fellas. my first time ever on the water this past weekend almost left me stranded and the bad thing is I forgot my paddle at home. Got it fired back up and high tailed it to the ramp. Have my cosmetics finished up on my boat now its time to concentrate on the engine. Boat has been sitting for 2-3 years and been ran maybe an hour total. I did get a good 1-2 hours out of it this weekend before it wouldn't fire back up. The lake is a lonely place when it gets dark. Fires up and runs every time on land with the muffs hooked up. Doesn't want to idle in the water.

I'm thinking I need to start with fuel pump, new fuel lines and carb rebuild. I have already replaced the starter, alternator, and spark plugs.

I guess my question is, can I use an automotive fuel pump? If so what year, make and model do I tell them at Advance? Also, distributor cap, and rotary button will be changed next.

I'm working on a 1981 Caravelle. Mercruiser 140. I have the manual downloaded, so I can get directions there.

Final question. How much of a pain is it to replace the exhaust/intake manifold gasket. I'm have a trickle of water, and an exhaust type noise coming out of it. Thanks for all your help, you guys have saved me a ton of money already. I'm not quite shade tree, but I'm not scared to turn a wrench either. Thanks, Mark

Will post some pictures of my upholstery work later. Thanks

Can you tell me were you downloaded your manual, I have the same year and model 1984 merc 140
thank you

 

[Bt Doctur]

Re: Merc 140 Fuel pump and other stuff

adults only section at the top of the page

 

[rocket350]

Re: Merc 140 Fuel pump and other stuff

Not that I reccomend this, but ask for a 1967 Chevy II 2.5L fuel pump. It's like 25 bucks.

I did this as a temp. 150 bones is a lot for a $400 boat that sat like yours for a few years. I wanted to ensure all the kinks were ironed out before dropping a lot of money into it. This gave me a month or so to get her on the water, run her hot, wot, adjustments, ensure outdrive, trim etc etc is working, tuned, and reliable. As you can see, boats are like women. She'll be fine in the driveway, but when you take her out it gets all bad and you just pray you can get her back home before things get even worse (and even your wallet)....

 

[m*a*baity]

Re: Merc 140 Fuel pump and other stuff

Not that I reccomend this, but ask for a 1967 Chevy II 2.5L fuel pump. It's like 25 bucks.

I did this as a temp. 150 bones is a lot for a $400 boat that sat like yours for a few years. I wanted to ensure all the kinks were ironed out before dropping a lot of money into it. This gave me a month or so to get her on the water, run her hot, wot, adjustments, ensure outdrive, trim etc etc is working, tuned, and reliable. As you can see, boats are like women. She'll be fine in the driveway, but when you take her out it gets all bad and you just pray you can get her back home before things get even worse (and even your wallet)....

Thanks for the info, I agree on the boat/woman issue. Found my problem. Cracked block. So bad its blowing compression, water, and some oil out of the side of it. Found a used motor and a mechanic to install for a grand. good thing I didn't buy the fuel pump. I first though it was just an exhaust leak. I guess in a sense it was, just didn't think it was that bad. Thanks for the info, I will remember that for later!