Mercruiser 140 bog and stall

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matthewpa

Cadet
Joined
Sep 4, 2006
Messages
27
Have a 1982 Thompson 18' Bowrider 140 Merc, engine only has 145hrs on it. Boat died and was not getting fuel this summer, brought to Merc dealer in town and they rebuilt the carb cleaning out all the crap in the carb from years or sitting in old man's garage. Additionally they did a complete tune-up on the boat replacing the plugs, etc.. Checked the aluminum fuel tank making sure nothing was in there. Everything looks good. Boat ran perfect for about 5hrs and then the same problem. Coming up on plane the boat died again in the middle of Lake Mendota in Madison, WI. Turns over fine, but just not getting fuel. Brought the boat back to the dealer and of course it started right up for them. They did a fuel pressure check and it was right within specs.
I have no clue what is going on, has anyone experienced a similiar problem? I need a solution! Please help.
 
M

mkpj1

Petty Officer 2nd Class
Joined
Jul 11, 2006
Messages
108
Re: Mercruiser 140 bog and stall

I here learning all I can about Mercs so I am o expert but Have done extensive work with muscle cars and hot rods. The pressure test at the shop is kind of bias (it was running of course). A field test or bench test would give more info. Basically try to get it to do it again. Pumps are notorius for being intermittent before they croak in cars. On another note, I had a truck I restored and fully rebuit after it sat in a field for several years. I went through several fuel filters before I got it all cleaned out. That was after new lines and a tank cleaning? Hopefully some of the experts here can give you more insight in regard to the Merc, Good luck
 
I

imported_rosco

Seaman
Joined
Oct 12, 2006
Messages
68
Re: Mercruiser 140 bog and stall

sounds like a fuel filter problem. there may be trash in the lines and or tank. there is no way they can look into the tank to check. you can pump the fuel out and chemically clean it however.

check the fuel filter. if it ran fine for 5 hours then died again, it really sounds like the filter is getting clogged.

also, many boats have more than one pick up built into the gas tank, its possible the sock on the pickup is blocked, try attaching the fuel line to the second pick up.

check the vent tube on the gas tank. if its blocked, it will run fine for a while untill ot builds up enough vacume in the tank then stop allowing fuel to go out, then once you stop, the pressure will release and it will run fine again for a little while untill the vacume starts building again.

done know how old your boat is, but after 1998 or so, the tempature sending unit can shut the boat off if it is getting to hot. same with the oil pressure, but either of those would act up within the first hour.

really sounds like the fuel filter though. check it. if its a rochester carb, there may be one inside the carburator as well as the external one.
 
M

matthewpa

Cadet
Joined
Sep 4, 2006
Messages
27
Re: Mercruiser 140 bog and stall

Well the dealer had the boat out on the water and ran it for 30 minutes up and down the river wide open with no problems. They commented on how nice it ran. I have no clue what to do about this problem. Not sure if it is a problem or not. All I know is they charged me $175 to drive my boat around and have found no issues.
 
Don S

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Mercruiser 140 bog and stall

Just went back and read your origina post and noted this.
Boat died and was not getting fuel this summer
Click to expand...

Your problem very well may have been vapor lock (FROM BEING HOT) something you will not see in most of the US between November and January. Or, it could be something in the tank that stuck on the pickup tube. I know you can't see everything inside of that tank because of the baffles. If you had the bow down when looking in the aft part of the tank thru the pickup hole or the fuel sender hole, everything probably moved to the front.
I don't doubt you have a problem, just have no idea what was done by you or the dealer an HOW it was done.
You need to do a fuel test like I linked to in the beginning when running the boat in the same kind of conditions. including weather temps if it was hot or rough seas if it was rough that day.
 
1

1978 century

Cadet
Joined
Jan 16, 2007
Messages
24
Re: Mercruiser 140 bog and stall

yea i would hook up a fuel gauge and then all you can do is drive it and see when it dies again if you lost fuel pressure..then cleaning the fuel tank and lines out ..new fuel filter and fuel pump..i know ur not positive that the pump is bad but if you do all that you should have no fuel problem
 
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