1979 Chrysler 72H9R 7.5hp outboard questions from a total boat noobie

[Bakon2]

got this motor from my father in law for free...attached to a 14ft john boat. Had some problems getting it to run at first but replaced the fuel lines as well as the oem metal gas tank. filled up the tank with 50:1 (non ethanol outboard fuel). The first time we took it out on the river for only about 15 minutes and it ran fine. Next time i took my 2 young kids down the river about a mile. That is about where we turned around because the motor started dying on me. It died about 8 times on the way back and I had to leave a small wake all the way home in the "no wake' zone. I also had to run it back on full choke. I tried to adjust the idle screw right on the carb tonight. I started it and let it idle for about 4 minutes. Turned it off and got the kids and headed up river this time, yes I learned my lesson. It ran great even at idle for about 5 minutes then it bogged down and died. I started it again and we headed down river and it died one more time so I gave it enough gas to keep it running...with a small wake. I have absolutely no idea what to check on this thing...I can't really afford to take it to a mechanic right now though. anyone have any ideas where I should start on this?
Edit: there is water coming out of the peehole.

 

[jerryjerry05]

Having to choke to keep running usually means the fuel pump needs a rebuild or the carb needs to be cleaned.
In the carb are small jets that get clogged.
​818043a 1 is the diaphragm with gaskets. F24748-2 is the other gasket. That's about all that you can change in the pump
Install a clear small filter between the carb and the fuel pump.
The fuel line connectors have a rubber seal that can go bad and suck air. Replace or remove them.

 

[fishrdan]

Yep, Jerry nailed it. Rebuild the fuel pump and see how it runs. Also, test the fuel hose quick disconnect by pumping up the fuel bulb and holding pressure on it, then closely inspect the quick disconnect fitting for leaks while moving the hose/connector around. If fuel leaks out, air will get sucked in (and cause all sorts of weird running problems).

If it still runs poorly, time to rebuild the carb.

If you need to replace the fuel hose quick disconnect, don't buy a Mallory. I bought one of them and it only lasted a couple trips before it was sucking air again. The second replacement (Sierra?) has been working fine for several years.

 

[Bakon2]

Ok, thanks for the advice. Once I get time I will start with the diaphragm, since that seems easiest, and go from there. I did notice one thing...if I pumped the primer bulb several times, fuel does come out of the fitting on the engine. Also, how do I get the bottom part of the cover off of the engine? I looked at replacing the diaphragm but I can't get to the screws...

 

[fishrdan]

I pumped the primer bulb several times, fuel does come out of the fitting on the engine.

Replace the quick disconnect fitting.

Also, how do I get the bottom part of the cover off of the engine? I looked at replacing the diaphragm but I can't get to the screws...

Not sue as I have a 87 Force, different cowl, but I do remember it being a pain to get to some of the screws for the fuel pump cover. You may not have to completely remove the cowl, just remove the bolts/screws and tip the cowl to the side.

 

[jerryjerry05]

When you squeeze the ball does it get hard?
Yes, the diaphragm might be ok.
If it had a hole it wouldn't hold pressure.

 

[Bakon2]

Thanks again for all the help so far...It doesn't seem to get too firm. I can keep squeezing it without much effort with just one hand. I just replaced it with a generic fuel line and primer ball. I had to cut the old tubing off from the connectors and reinstall them on the new lines. What confuses me is that it runs great...until I get far enough from shore that I don't really want to row back...and dies. Then I have to pull the starter cord several times to start it again and it dies after a minute or so unless I have it at full throttle or close to it.

 

[Bakon2]

Replace the quick disconnect fitting.



Not sue as I have a 87 Force, different cowl, but I do remember it being a pain to get to some of the screws for the fuel pump cover. You may not have to completely remove the cowl, just remove the bolts/screws and tip the cowl to the side.

I will look on here for one of the fittings...and I will also look at how to remove the cowl tonight...thanks.