75 hp 1982 Chrysler dies out with throttle

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Ok guys first I wanna thank you for all the info ive found on the forms, I've recently rebuilt a transom in my 19ft Aries 200xlt bass boat and it was invaluable, i have picked up a motor on the super cheep to power my 19ft bass boat (75 hp Chrysler 758h2e) yes I know it's extreamly under powered but it was the most I could afford being a broke college kid, the motor ran but not very well when I picked it up it would die at anything above 1/2 throttle, thinking a simple carb cleaning would help I picked it up, there was a TON of junk in the carbs I cleand them out set the floats correctly and re asimbled the motor runs much better and smother but still seems to bog down and eventually die at 3/4+ throttle being underpowered I need that little bit to get on plane, new plugs, new fule lines, cleaned fuel filter, good compression, im at a loss original owner mentioned something about timeing but I'm not sure I'm that skilled to embark in that endeavor....... any advice would be appreciated!
 

Tnstratofam

Commander
Joined
Aug 18, 2013
Messages
2,679
Welcome to the best place for everything boats on the web.

Sounds like you've replaced quite a bit of the fuel system. Did you install a new fuel pump? Also I installed a clear fuel filter between the fuel pump and the carbs to help insure I can visually see fuel being pumped to the carbs.

There is a timing tutorial in the stickys at the top of this forum, However I think it sounds more like a fuel problem than a timing one.
 

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Thanks! I'll put one of those filters on tonight after work and take her down to the launch and see if I'm getting good flow, I have not re-built fuel the pump as I'm trying to do this in a restricted budget would the only part I need be the diaphragm? I doubt I can find an entire replacement part... I'll let you know how tonight goes!
 

Tnstratofam

Commander
Joined
Aug 18, 2013
Messages
2,679
Should just need the diaphragm. One other thing to watch for is if the primer bulb is staying primed. If it isn't it can be an idication of air sucking in at the tank fitting or the bulb itself. If your running and the motor starts to loose power and you squeze the bulb and the motor picks up rpm this can be an indication of either a bad fuel pump or a leak in the tank to bulb to motor lines.
 

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Ok I had a buddy sit in the back and work the bulb but still no diffrence saw fuel running through the filter as it should, ordered the diaphragm and the pump gasket so we will see how that works when it arrives this week... on another note my buddy thinks that I have a blown head gasket beacuse of Thea small amount black oily soot that is right around the head gasket of clyender 2 and 3 could this be my problem? I feel like even if it's slightly leaking it shouldn't cause the motor to completely die at higher RPMS. My understanding is that there is a channel of water running through so there would be no possible way for the black soot to escape....
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Do a compression test.
Take a 1/2" socket or wrench and try to tighten the bolt next to the oil.
That not work? Pics?
Post comp test results.
 

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Compression was re tested with a better guage not good but even and over 100, I did see that to PO had glued wires together on the ignition I filed that down and held them to gather and it seemed to run better at the launch but I couldn't let go of the wire, new ignition is on the way, I also added more gass and a bottle of ISO heat per segustions of a marine mechanic one of those seemes to be my issue I'll let you know how she runs with the new ignition when it arrives
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
The important thing is all 3 are close.
100 is real low but that could be the gauge???
 

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Very possible it's the guage, the guage was a "rental" from an auto parts store, giving me compressions of 90 psi for cly #2, 97 in cly #1and3 the first time, higher with the 2nd guage but still about the same difference. noticed that the spark plugs have a heavy coating of black soot so I'm thinking she is running a little Ritch.... gave up on waiting for the new ignition and soldered the old one together gonna go tinker with it more in the water tomorrow
 

Jza

Cadet
Joined
Jun 17, 2017
Messages
13
Turns out it was the timing, looks like PO set timeing at idle not full throttle, got her going great and went on an epic fishing trip on leach lake today! thanks for the suggestions
 
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