Logo

1974 Chrysler 75hp no power and won't stay running

Hardie_boi

New member
A couple of months ago I bought a 1970s Fi-Glass Fireball with an old Chrysler 75hp motor on it (model number 757HA). The motor wasn't running when I bought it (it had a CDI issue) but I replaced that with a regular automotive coil and it ran great until last time I went to take it out and it had no power and was really hard to keep running. It wouldn't start unless you opened the throttle and as soon as you tried to idle it, it would cut out. I brought it back in and checked the compression and it all seemed ok. One of the plugs was damaged and I replaced that but it still has the same issue. It also seems like a an unusually large amount of water is coming out of the top exhaust port on the back of the motor. I'm unsure if that is something to do with it or not. Does anyone have any ideas as to what it could be?
 
Post a picture of the " damaged " spark plug.-----You did replace the water pump impeller I hope.-----Mixing gas and oil at 50:1 in your tank ?-----
 
Post a picture of the " damaged " spark plug.-----You did replace the water pump impeller I hope.-----Mixing gas and oil at 50:1 in your tank ?-----

I checked the impeller when I had the bottom end apart which I replaced some seals on and it was good. Spark plug looked normal, it just had no continuity through it. And yes I have been using 50:1 with proper marine two stroke. There could be a possibility it was bad petrol as it was from a company that, here in NZ is not well known for their quality. However I put the tank on my 15hp Yamaha on my dinghy and it ran perfectly fine.
 
Occasional pop or backfire sounds like it could be a sheared flywheel key?
Bad diaphragm in the fuel pump?
Check the compression on each cylinder and check for spark.
 
Blunt statement.------Your motor is not running properly.-----Guessing / assumptions do not work.-----Organized trouble shooting will quickly determine what is wrong.
 
Back
Top