45hp chrysler stalling problem

[meatloafsandwich]

Hello all, well this is my first time posting here but not my first time getting excellent advice from here. So here is my issue: I have a 1978 Chrysler 45hp (model457H8J) she starts on the first pull(starter is shot) and will throttle up just fine in "warm-up" but when I put it in gear, anything more than idle, makes it stall! I do not know much about boats, so excuse my ignorance. Please help if you can and I will be in debt forever.

Thanks

 

[bustermin]

Re: 45hp chrysler stalling problem

you dont mention any trouble shooting you have already tried, that would be helpful to know what you have already eliminated. and i have to assume you have fresh gas in the tank. so, my first question would be, has the motor been sitting for any length of time? if so, then you could need a carb cleaning/rebuild. have you checked the fuel filter, it may be plugged, also check the pick-up tube in the tank. also may need fuel pump. do you have a strong spark, it could also be an electrical problem but without any more information it will be hard to tell....

 

[meatloafsandwich]

Re: 45hp chrysler stalling problem

uuggghh, dork points for me!! thanks for the reminder. so the motor has new plastic fuel tank, rebuilt carb, battery, coils, points and condensers, wiring troughout. I also forgot to mention that it ran great for about two minutes, planed out, got to top speed, then that is when I felt the rpms slowly drop then stall. someone mentioned reeds.??

 

[bustermin]

Re: 45hp chrysler stalling problem

what was the origonal problem that made you decide to change so many parts, that too may be helpful in this diagnosis, while it could be the reeds, i would tend to lean towards what somebody has touched first. it sounds like it is starving for fuel, so i would double check the carb adjustments. but it wouldnt hurt to double check all and anything that has been touched. also you didnt mention the fuel pump, is there a reason why after changing all the other things you didnt change the fuel pump? if there is a very small hole in the diaphram it will not pump enough fuel to the engine. you also say that anything over an idle it stalls, when it stalls does it act like it is trying to rev but cant, or does it just shut off like you hit the kill switch? did you double check the points, are they still adjusted correctly, they may have moved enough to let it run at an idle but when you rev the motor there is not enough juice to ignite the fuel in the chamber (similar to when a car alternator goes out and the car runs on the battery alone)

 

[meatloafsandwich]

Re: 45hp chrysler stalling problem

bustermin,
thanks for the quick response! the reason i changed all those parts was because when I bought it there was no spark. One of the coils was physically cracked, replaced coils, still no spark, did some tests that I saw on these forums, replaced points/condensers and fired her up, then I noticed trash in the fuel bowl after running rough. kicked the metal can to the curb, put in plastic, rebuilt carb. and the story starts from there, the reason i did not do anything with the fuel pump yet is because i do not know much about boats and i was told by a few (unreliable) people that if the fuel bulb was still hard after shutting off that the fuel pump was good and with the cost of the fuel pump and reeds, I do not want to replace something that does not need it. when it died the first time, it went down slow and steady. now it is like you are shutting off the motor, if the fuel pump is bad, would i still be able to throttle it up in "warm up"? I saw a rebuild kit for the fuel pump, would that be a good investment? figured I should ask the pros here before spending money on advice from a motorcycle mechanic.

 

[myanni74]

Re: 45hp chrysler stalling problem

I have a very similar motor. Mine is a 1974 457HH 45HP Chrysler. I was having a difficult time with it stalling at WOT as well as whenever I put pressure on it. After many changes, I found out a few things. Check the simple stuff first. I hate to sound like I am over simplifing it, but did you check to make sure that the vent cap screw on the plastic gas tank was up? That can easily chock out the motor.

The other issues that I had were that the hose clamps on the fuel line were weak and I was losing pressure through there. Also with the older Chryslers, you should check to make sure that the air chuck style fittings are also good. I had to replace mine when I replaced the fuel line. You could also have a cogged carb. I purchased a SELOC book for mine and it was very helpful with some great illustrations on taking the carb apart and cleaning it.

Finally, to rebuild the fuel pump diaphram for this motor, it is actually pretty cheap and about 1 hour worth of work. The part number for mine was 18-7806. I think it was like $20.00. I found a good amount of parts at www.chrysleroutboards.com . Good luck. Once you get it working, it will all be worth it.

 

[bustermin]

Re: 45hp chrysler stalling problem

i would recheck the carb settings. as i mentioned before, the problem is most likley with somthing you touched. also give your fuel line a close look (inside and out) a weak or plugged fule line can cause a lack of fuel. with all the work you have done, you should replace the fuel line (an inexpensive repair) going to the fuel pump and from the pump to the carb. have you tried pumping the bulb when it tries to shut off to see if it will continue to run? or try squirting a little fuel into the carb while it is running to see if it will continue to run.

 

[jwhall]

Re: 45hp chrysler stalling problem

I have the same outboard motor as meatloafsandwhich (4578HJ) and was wondering if anyone has the part number for a starter and a choke. Just bought the boat and need to replace these. Any help would be appreciated.