75 hp Chrysler Fuel problem

[Todd N]

I have a 75 hp chrysler Model 757H8D (1978 I believe). Was out with the boat and the motor just died. Narrowed it down to a fuel problem by hitting the carbs with fuel mixture and it fired. Bulb pumps firm and I have fuel at the filter and it will flow out of the pump when I disconnect the line to the carbs. I am at a loss as to why it happened all of a sudden. It was running great right up until it was fuel starved. No rough idle or anything.

 

[eurolarva]

Re: 75 hp Chrysler Fuel problem

Did you try removing the float covers on the carbs to see if any gas is in there. If needle valve is stuck closed you wont get any gas.

 

[Todd N]

Re: 75 hp Chrysler Fuel problem

I dropped the covers and had gas in all 3. Floats moved freely. I cleaned the carbs and tried again. Got it started and in dies at idle but if I give it some throttle it runs smoothly. My next step is to change out all the gas lines and bulb. Do you think I am on the right track?

 

[eurolarva]

Re: 75 hp Chrysler Fuel problem

Sounds like you are on the right track. I recommed to everyone to replace fuel pump diaphram, rebuild carbs and replace fuel lines. Here in minnesota we have oxygenated fuel with lots of alcohal in it. That stuff dries rubber out pretty fast. I dont know what you are using but if you have any water in those carbs it could be giving you grief. Diaphram for fuel pump is under 10 bucks and easy to install. I only have one carb so you have more grief and cost then me. Good luck

 

[Todd N]

Re: 75 hp Chrysler Fuel problem

Ok, replaced the fuel lines and still runs rough at idle. I have fuel blowing out of the top carb. Looks like I need to rebuild the carbs. Anyone have any suggestions on getting rebuild kits and a new fuel pump kit? Being an old motor, not sure where to go from here. Thanks again for any help.

 

[eurolarva]

Re: 75 hp Chrysler Fuel problem

NAPA has them part number 18-7037 carb kit is about 15 bucks NAPA part number 18-7806 fuel pump rebuild kit is about 10 bucks. I dont recommend doing the fuel seats on the pump. Just do the diaphram, gasket and the fuel bowl screen and gasket. Two of the fuel seats are press fit and are almost impossible to get out without breaking. If the gaskets look bad on the seats you will have to remove them. If you break them I can give you a part number for them<br /><br />Good luck

 

[cicerofire]

Re: 75 hp Chrysler Fuel problem

Todd, I have the same motor and had the same problem 1 new fuel pump rebuild and three carb rebuilds later she is back to running like a dream and starting on the first bump of the key. Good luck to you, keep us updated as I learn something every time I touch mine, and this forum has been a life saver as well. Glad to see another 78 75hp owner on the boards. I love mine, she actually starts better than my 2004 Merc!!