Chrysler 140 running out of gas

[GMjonn]

OK.So I have a 1979 Chrysler 140 outboard that has a lack of fuel/bogging problem. The engine runs then bogs down and quits. I had orginally thought it was a fuel pump problem and I replaced all the fuel pump diaphrams. After that didnt solve the problem I checked compression and found I had one cylinder reading low and thought that it was a low comprssion/lack of vacuum problem and I parked the boat, saved my pennies and rebuilt the power head having the number 2 cylinder bored. I installed 4 Weisco piston and ring sets,new Boyseen reeds, set the float levels, new timing belt, and new impellor. Take the boat out on the lake, and BAMM same bogging problem. Pull the tank, remove and inspect fuel pick up, no visible problems. The boat is a Conqueror 140 with a 18 gallon rear tank. I have run the boat with the engine hood off to eliminate the possibility of and exhaust leak filling the hood with fumes. When I rebuilt the engine I also replaced the fuel line, primer bulb and quick disconect. Thinking that maybe the quick disconect is not passing enough fuel I bought a fuel barb, removed the quick disconnect and hose clamped the 1/4inch fuel line to the fuel barb. Go out on the lake and it's still bogging. go buy a fuel pressure gauge and install it between the fuel pump and the carbs and I get 3 to 4 PSI at idle and 5 to 7 when I blip the throttle open for a second when move the bar that ties the two carbs together. When I take the boat out now I can see that it runs for about 2 minutes at a 4k throttle setting before it slowly looses fuel pressure, faster if i run over wakes. Does it sound like the fuel pump is loosing prime, and is there suppsed to be some kind of anti siphon valve? I'm in the lake Lanier area of Georgia, is any one who reads this in that area? Thanks for any help you can give me.

 

[pnwboat]

Re: Chrysler 140 running out of gas

Check to make sure the vent in your tank is open, or the pickup tube in your tank is not clogged or restricted. I would try using a known good portable tank to see if this has any affect. If the problem goes away, then that would point to a problem in your 18 gallon tank.

I would also replace the 1/4" line with at least 5/16" or 3/8" if possible. May have to change some of the barb connections when going to 3/8" line.

 

[Frank Acampora]

Re: Chrysler 140 running out of gas



Your fuel pump pressure is right on. No problem there.

Definitely replace the 1/4 inch line--it is insufficient for the fuel needs of that engine. Go 3/8 with everything if possible.

Then check the routing of the fuel pump hoses: The lower pump should feed the upper pump and the upper should feed both carbs. It should NOT be one pump for one carb.

I have a couple of 140s and if you look into the carbs when you bang then open, you would NOT believe the amount of fuel vaporizing in the venturis of those puppies.

ALSO: The inlet holes in the seats in the carbs are relatively small.

1. Be certain that you have enough float drop to pass sufficient fuel.

2. Check to see if the seats have swelled, partially closing the holes. If so, replace the needles and seats. These are press-in so if you remove them to check you WILL need to replace them.

I have a 105 that has the same bogging at full throttle. In my case, I narrowed it to poor crankcase vacuum and compression due to standard pistons installed in a .010 oversized bore. In your case, you have already rebuilt the engine so crankcase compression and vacuum is not an issue.