Chrysler 75 HP Quits on power demand.

[Wayner]

Hello and thanks for taking my question. I'm an auto mechanic but have never worked on a boat. We just bought a boat with a 75 HP Chrysler outboard on it with electronic ignition not sure of the year but I'm guessing late 70's. (If anyone knows what the year is that would be great) Model # 757B8D Ser# 1027. We have only had the boat out twice. The first time it didn't run too bad but it had a miss at higher rpm. The second time we took it out it would only go very slow. When you try to speed up it would quit completly. Then when you try to start the boat it cranked over fine but would not start while cranking, when you let go of the key and stopped cranking then it would start. This tells me there is not enough voltage to the ignition system while the starter is drawing current. The reason I know this is an igniton problem and not fuel, is when I got it home I put it in a barrel of water and did a spark test. I just inserted a wire into a spark plug boot so I could watch it spark to ground as the engine was running. Everything looks good at an idle, but as I reved the engine higher and higher the spark all of the sudden quits completely and the engine stops. I was telling you it won't start until you quit cranking, the funny thing is the first time you start the engine say in the morning, it starts normally while you are cranking. Then when I rev it up and it quits, then it goes into not starting until you let go of the key. (Very strange) The battery is brand new and shows 12.5 volts when the engine is off. While running the voltage is around 13.0. I show the same voltage at the ignition terminals inside the engine compartment so it's not bad cables or anything. I wondered if maybe the voltage was still too low so I hooked up jumper cables from my truck and then had voltages of 13.6 but when I run the boat engine it behaves exactly the same way. I talked to the boat shop that has worked on the boat before but they were not much help, they did say the CDI had been replace about three years ago part # 523301-1 and the Pre-amp module was replace last year. Any advice you could give would be very much appreciated. Thanks

 

[Bear]

Re: Chrysler 75 HP Quits on power demand.

# 757B8D? Is it 757H8?<br />This is what i have:<br />757 HA, HB, HC, H8, H9 75 1974-79<br />Maybe it is a 1977-78?<br /><br />Try this link: <br /> http://outboardparts.com/chrysler/miscellaneous/troubleshootinghelp.htm <br /><br />I hope it helps.

 

[icwebpeople]

Re: Chrysler 75 HP Quits on power demand.

its a 78. pull the flywheel off and check the stator under it. if you see jelly ooozing out its shot.

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

I pulled the flywheel off and the stator is in good shape, just a little rust on the magnets that I cleaned off.

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

I pulled the flywheel off and the stator is in good shape, just a little rust on the magnets that I cleaned off. The only bad thing is, I forgot to take the timing belt off first and it ripped in half now I have to get a new belt before I can try it again.

 

[lonewolf5347]

Re: Chrysler 75 HP Quits on power demand.

TRY READING OHMS ON STATOR SHOULD HAVE A HIGH @ LOW SIDE .MULTIMETER SET TO OHM'S X 1000 SEE WHAT THE READING ARE.SHOULD BE AROUND 650

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

Thanks for everyone's help so far, I will keep you posted of my progress.

 

[Terry H]

Re: Chrysler 75 HP Quits on power demand.

Wayner...I don't think the charging system will affect the ignition in thatta way...you should be looking at the ignition...maybe points need repaired or electronic sensor needs cleaning or even worn cam in distributor. just a Thought

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

New update on Chrysler 75 problem. Since I last posted I took the boat to a so called mechanic but I'm still haveing problems. He found the reason it would not rev up was the Pre-amp was blown(the pick up module in the distributor)he also replaced the rotor. It would then rev up fine out of the water but when put in the water and put into gear it would do a strange kind of chugging and then eventually power out and die, before we even got moving, the mechanic played around with it so long that it finally would'nt start at all. We pulled it back to the shop where he found the pre-amp had blown again. He replace it again and also replaced the ignition switch. He claimed the switch was shorting out and thus burning out the pre-amp. Now its back to running the same way again, fine out of water but will not pull a load. To me it's still got some sort of ignition problem. Not all the time but sometimes when you crank it to start the engine, it kicks back on the starter just like the timing is too far advanced. Then it may or may not start, and sometimes it sounds like it's running but if you look at the flywheel its turning a half turn forward and then a half turn backwards. It will do this repeatedly until you turn the key off. I think one cylinder is firing forward, then the next cylinder is doing that kick back thing and firing backwards. The mechanic says the timing is set right on 28 degrees. Seems very stange to me, I'm about ready for the dynamite. The mechanic is basically lost, he's now searching for other problems. He's checked the head gasket and it's ok. The compression is good, the carbs are good. The CDI checks O.K. I wish I could find and old distributor with points and condenser to replace this electronic crap. If anybody has any thoughts or if you know where I might find an old distributor it would be most appreciated. Thanks

 

[icwebpeople]

Re: Chrysler 75 HP Quits on power demand.

check wires and cap, then check to see if dist is in sinc with throtle

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

Cap and wires are good. Does anybody know the procedure for setting the timing and adjusting the distributor and throttle rods. The mechanic is lining up the T on the distributor gear with a mark on the flywheel and says it's set a 28 degrees. I would rather see it set with a timing light to be accurate. When is it at 28 degrees? I assume at full throttle. Shirley it would not idle very well, that far advanced. I guess I need to order a technical manual for this motor.

 

[Terry H]

Re: Chrysler 75 HP Quits on power demand.

Wayner...with the motor at tdc on #1cyl, which should be the 0 degree mark, line up the distributor mark to the flywheel and set the belt and tighten the distributor. The timing is set with the 1/4" machine screw that is attatched from the tower shaft to the destributor. You can set it statically (without running) using a 12v light attatched to the hot side of the points. If you can't figure it out I will be in town monday and can add some more detaild. I have dont this many times and it works very well...just a Thought<br />If you can make sense of what I just said you will have no problem with this simple task...

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

Thanks for the info, however this motor doesn't have points. It has a pre-amp which triggers the CDI. I have a timing light but do you know what the timing should be set at for the idle position?? I'm thinking it must be set too far advanced right now, thus making it kick the starter back on start up.

 

[bestshot]

Re: Chrysler 75 HP Quits on power demand.

Clymer - has a very good outboard shop manual for crysler 2.5 to 140 hp - 1966 to 1984.... Its got all the information you should need. Its a must have for an older chrysler ob owner.

 

[icwebpeople]

Re: Chrysler 75 HP Quits on power demand.

do you have a black wire and a white wire on the front side of the distributor?

 

[Terry H]

Re: Chrysler 75 HP Quits on power demand.

Wayner...you don't set timing at idle on this motor...you set it at wot. If you could find a Seloc manual that covers this model it shows you exactly how to do what you want to do...You don't need a timing light, you need a 12v test light...If you need to use the timing light you can take the plugs out and set the timing using using starter to turn motor...just a Thought

 

[Terry H]

Re: Chrysler 75 HP Quits on power demand.

Wayner...did you ever git that motor runnin' right?

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

Got the boat home a couple of days ago but just had a chance to look at it today. I think I see what the "so called mechanic" was doing wrong. He was using a 12v test light to set the timing (just as you described thought) I never actually seen him setting it but I assume he was setting it at 32 degrees just at the point when the 12v light went out. This is would be the proper procedure if the engine had points, because that would colapse the field in the secondary coil thus causing a spark. However when I did some testing I found the spark was created when the 12v test light first came on not when it went off. When I checked where it would be set using this procedure I think he had it set at 50 degrees or more. It got dark before I could reset it and try it out, but that will be tomorrows project. I hope that is all it is. I will keep you posted of my progress tomorrow and I really want to thank everybody for all the help so far, it is very much appreciated!!! Thanks.<br /><br />WR

 

[Terry H]

Re: Chrysler 75 HP Quits on power demand.

Wayner...if you don't have points than you unhook the blue wire at the dist and hook the light there, set the timing when light turns on...one more thing I would set timing about 2 degrees retarded from what the specs call for...30 btdc...poor gas these days you know...I'm saying this from memory, always check the book...just a Thought and good luck

 

[Wayner]

Re: Chrysler 75 HP Quits on power demand.

Yipee, yahoo!!! I think I finally got it. Thanks again for everybody's help. Once I got the dist. lined up properly and set the timing it runs like a top. I still have to put it in the water for the final test, but I'm sure it will be fine, it runs so much smoother now than it did before. The guy I had working on the boat had the timing really screwed up,I'm sure it was at about 50 degrees advanced at an idle. It's little wonder it would stall when put under a load. It's a wonder it even ran at all. My only hope now is that it will stay running and not burn out that pre-amp (module in the distributor) again. Thats what started this whole thing in the first place. The guy I had working on the boat claimed the new ignition switch should help that problem. But I don't trust his opinion anymore for obvious reasons. Has anybody heard of any other reasons why these little modules blow?