1975 Chrysler 45 hp loosing power at full thottle

[conor1366]

I am new to Chryslers and have found a great group of helpful folks willing to give great imput on all sorts of issues.

Issue#1- I had the motor on the lake this weekend and it was full throttle and the motor lost power and cut off at full bore after 2 minutes. It only did it one time all day. When I tried to restart the motor it seemed it was flooded and I waited 10 minutes and fished, then it started right back up.

question- I saw a thread with advice from Eurolarva and he said it may be the fuel pump.

any advice would be helpful

 

[jerryjerry05]

Re: 1975 Chrysler 45 hp loosing power at full thottle

Clean the carb.Make sure there is no water in the gas.Then rebuild the fuel pump.That should take care of it.Jerry

 

[conor1366]

Re: 1975 Chrysler 45 hp loosing power at full thottle

my mechanic that checked the compression checked the fuel delivery and said it was good..what that means I don't know.

I checked the screen on under the black cap on the side of the motoer...that clean.

the gas is new and there should not be water in the lines.

the only other thing is the fuel pump. what does the rebuilt entail?

 

[eurolarva]

Re: 1975 Chrysler 45 hp loosing power at full thottle

9 out 10 times it is just a diaphram. 18-7806. Kit can be purchased from iboats or NAPA. Just remove the fuel lines remove fuel pump from motor. Remove a couple of screws. Replace diaphram and gasket put screws back on and re hook up. First time you do it maybe an hour second time maybe 15 minutes. The other 1 out 10 times it can be one or all the check valves in the pump. Do the diaphram first. If you still suspect the pump replace all three check valves and gaskets. they are 5 bucks each plus fifty cents for each gasket.

 

[conor1366]

Re: 1975 Chrysler 45 hp loosing power at full thottle

NAPA sell outboard parts? What about the other auto parts retailers?

I will try the diaphram first. If I change this then do I need to change the gasket by default?

 

[conor1366]

Re: 1975 Chrysler 45 hp loosing power at full thottle

Eurolarva was correct. The Diaphram was cracked and dryrotted out and the gasket I had to scrape off with a razor blade. I don't think it has been replaced in 35 years.

Next I am going to check the connections and the o rings on the fuel line for air leaks.


I am recieving my rebuilt lower unit today and hope to have the engine back on the water for the 4th.

 

[eurolarva]

Re: 1975 Chrysler 45 hp loosing power at full thottle

If you are going to keep that motor you should get a manual. I like Clymer because it explains things a factory manual does not. Also I recommend getting a factory manual and parts list from chryslercrew. They are pretty reasonable and downloadable and open with acrobat. When you get around to it you should replace all the fuel line and maybe rebuild the carb. The carb kit is around 20 bucks and fuel line probably another 10 bucks. The rubber is probably all rock hard and is due. If you have fuel related problems you will need to do these things but start with the simple things and only do one thing at a time. Like dont do the fuel pump and the carb at the same time. If something goes wrong you will second guess your work and not know where to look. Maybe start with fuel pump then do all the fuel lines and towards the end of the season do the carb.