1978 75HP Chrysler Problems

[rich83]

Hi guys!
I have been doing tons of reading on this forum and it is great!

Well I just bought a ski boat for $250.00, which included two 75 HP chrysler motors. when I bought it the guy fired it right up for me, but i had to change the water pump, since it was bad when he fired it up.

Now the engine will only fire "1" time and pop and have some smoke come out of it. It will turn over all day, and it is getting sparks to the plugs. I just installed new plugs, drained the gas, drained the bowls and cleaned them a little.

Any ideas on what to do. I have a whole other engine that is supposed to run for spare parts.

Thanks!
rich

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Sorry model # is 757H8D

 

[eurolarva]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Try putting the old plugs back in. Are you sure you hooked the correct wires to the correct plugs? Sounds like your timing is off and this can happen by hooking the wires to the wrong plugs. What plugs were in it and what plugs did you put back in it?

The model number you posted is from 1978 and calls for champion L20V

 

[Frank Acampora]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Ahhh--the previous owner started it, but did he tell you the correct starting sequence? Cold engine--first start--Squeeze the fuel line bulb to prime the carbs. Squeeze until it gets hard--usually around 5 or 6, not 1, not 20. Remember, you are filling 3 carb bowls. With the control handle up in neutral, pull out the chrome or silver knob. This disables the shift. Now push the control handle as far forward as it will go. This is start/fast idle position. Now turn the key while simultaneously pushing it in to choke the engine. Release key when it starts. After a few seconds at fast idle, slow it.

Put it back into neutral and press in the chrome or silver button. Now, a quick snap into gear and you are ready to go. Do not ease it into gear. This wears the drive dogs in the lower unit. It is normal to hear a thump or clunk when the engine goes into gear.

Some of these engines just will not start at all if they are not put in fast idle when cold, and none will start cold without choking a bit. Don't overdo it or you will flood it.

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

I am thinking it is timing.
The old plugs in it were the wrong plugs. Looked like vehicle plugs didn't have the flat bottom.
I installed the L20V champion plugs that it calls for with the flat bottom. The plug wires should be right. I don't think the wires will actually reach the other plugs.

It will fire one time and smoke. I have been doing the correct starting sequence.

So would it be timing. It has a factory timing sticker on the flywheel, but the old owner has scratched a new timing mark into the flywheel and it lines right up with it. I did change the timing to the 32 degree mark and it seemed like it would not fire hardly at all then. So i changed it back to the scratched mark that the original owner put on the flywheel and it fired a couple of times and did the same thing.

I don't know what to do. I am new to outboards, but am pretty good with vehicles and working on many other things. Outboards seem to be a pain at times.

You said to put it in fast idle, but when i engange the fast idle it seems not to be doing anything different to the carbs.

I did change out the lower unit with my other motor due to the water pump was bad and I could not get the screws out of the one orginally from this motor, but this should not be effecting anything should it?

Thanks! rich

 

[Frank Acampora]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Getting late so I will just give a couple of hints then come back tomorrow. If the owner scratched a new line on the flywheel and it is significantly different from the original location, something is wrong. It could be a sheared flywheel key. It could be an improperly adjusted distributor.

To check the flywheel, take out the plugs and put a screwdriver into the top plug hole. Turn the flywheel clockwise until the screwdriver reaches top dead center. Rock the flywheel back and forth to confirm TDC. Check the 0 mark on the flywheel against the pointer on the manifold. If significantly different, (like more than 4 degrees) the flywheel key has sheared.

Top cylinder is #1 and firing order is 1,2,3. #1 plug wire is (if I remember correctly) the wire on the distributor nearest the block.

With the flywheel at TDC, the pullet on top of the distributor should have the curved line matching the flywheel with the straight line pointing directly at it.

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

ok, I check TDC how you said, and it is right at the 0 mark.

While it is at the TDC mark, the distributor lines right up with the scratched in mark? Is this correct?

Not sure what to do? Could it be the carbs? The backfire is not real loud just a small backfire when it starts. More like a little pop.

Thanks! any help is greatly appreciatted!!

 

[eurolarva]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

I am no help on the timing however when the guy tested the motor for you did he use water muffs or no water at all? If so do you have it in a tank or on muffs? If you have a dead cylinder you will notice it more in a tank or body of water then you will with water muffs.

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

I have it in a barrel of water. It is hard to even get it to fire though.

Then when it does it will only fire one time.

So there is somthing different wrong than just misfiring.

I think I might bring it into the shop and see what they can do.

I have a whole spare motor for parts, so that should save some money.

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Ok,
Just wondering if flooding could be causing this?
Like a bad/stuck float or somthing?

I noticed that my second carb is getting a little gas puddle through the front, that flings out when i use the choke. The other 2 carbs arn't having this problem.

 

[rich83]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Well, I am lost now.

I pulled the flywheel, and checked the woodruff key, and it is fine. I installed a new distributor belt. I am pretty sure the timing is good. The flywheel is at TDC 0 degree mark, and the distributor curved line, lines up with the flywheel. When i turn the key to the on position and rock the flywheel i can hear the distributor sparking + or - 2. The gap between the two plastic pieces on this distributor are at 3/8 - 1/2 inch apart. I pulled the carbs and cleaned them and checked the floats and they are in good working condition.

So I don't know what to do. I am still getting one backfire when trying to start the engine. The backfire comes out of the exhaust, with smoke and thats it. The engine won't start.

Could me changing the lower unit have anything to do with this? What gets me is the guy I bought it from said "The engine runs great, and walked right over and fire it up without any problems, and without saying its has not been ran for awhile, so it might not start easily." He was very confident that it would fire up.

Thanks and any more ideas are appreciatted!

Anyone from the Southern Illlinois area that is good at working on outboard motors?

 

[Capt Ron]

Re: 1975 75HP Chrysler Problems

Re: 1975 75HP Chrysler Problems

Have you run a compression check on it?
Is it possible that this motor may have had this cold starting problem before you bought it? The seller may have ethered it and warmed it up before you arrived and then just hit the key for you.
Pulling the lower unit shouldn't have any effect on this problem.


CaptRon

 

[ybor_knight]

Re: 1978 75HP Chrysler Problems

Have you had any luck yet? I have a 1978 Chrysler 115hp with the Motorola distributor system and I'm having the exact same symptoms. I noticed the wire going into the coil felt a little loose and when I wiggled it around a little it ran for a few seconds a couple times, but now still just trying to fire then popping. Know the coils getting a spark though because it lit me up pretty good once when wiggling it during start. Pulled the distributor cap and one of the wires had a lot of corrosion so I cleaned it up and then it started for a few seconds dry and I had to hurry up and shut her down. Once I filled the barrel to test, it wouldn't start again and was doing the same firing once or twice then popping and smoking.

 

[rich83]

Re: 1978 75HP Chrysler Problems

Still nothing, getting the same thing. The compression on all 3 cylinders are fine.

Not sure what to do now?

I have extra parts, i may change out to see if it helps.

I am wondering if I am just getting a weak spark, the clymer manual I have says that is releated to the backfire out of the exhaust.

 

[ybor_knight]

Re: 1978 75HP Chrysler Problems

I just spoke with a guy who has worked on theses motors for 25 years. I was thinking that the coil has gone bad, but he says they rarely do and that he's only needed to replace 3 that were bad in the 25 years. He says its usually the capacitor in the CD box that goes out.

 

[rich83]

Re: 1978 75HP Chrysler Problems

There is no way to change the capacitor in the cd box is there? Have to buy a whole new box, and they are pretty expensive.

 

[ybor_knight]

Re: 1978 75HP Chrysler Problems

Yeah, there's no way of replacing the capacitor. The cheapest I've found the CD units is about $250. I'm still trying to figure out how to test all the different parts in the ignition system in order to isolate the bad part. I don't want to buy a CD unit until I know everything else checks out.

 

[ybor_knight]

Re: 1978 75HP Chrysler Problems

Had any luck yet?

I got mine running last night. I decided to check the simple things last night before spending anymore money and it ended up being the firing order. Not sure how it happened because I replaced one plug at a time, but she running now. Only problem I'm having now is the idle. When you bring the throttle back to the idle position, it doesn't actully idle all the way down. You have to reach back to the motor and push the little throttle mechanism back manually.

 

[rich83]

Re: 1978 75HP Chrysler Problems

No, no luck yet.

My fire order is. If you are looking directly at the distributor cap the back left plug is on the top head cylinder, then number two is on the back right and on cyclinder #2 and the next one on cyl 3.

I did find somthing else out though.

When i check the pressure with a gauge it shows 110 on each cyclinder.

but the top plug has a heli-coil in it, and when looking at the spark plug on cyclinder 1 there is oil that gets blown out on the plug about 1/2 inch.

Would this cause a backfire if the cyclinder was losing its pressure?
If so how would I get a nice snug fit of the plug?
Thanks!

 

[rich83]

Re: 1978 75HP Chrysler Problems

GOT IT RUNNING!!! The motor starts everytime, well I did it about 20 times in a row, with about 5 minutes break in between, and fire right of the bat everytime!

I changed the head due to compression loss on the first cyc because the heli-coil.

The problem now is I am having water leak around the plug on cyl #2. Also the other problem is linkage adjustments because it dies in nuetral, and does not pick up speed untill the handle is more than halfway up. I have the clymer book and it seems to give pretty good instructions for tuning all the linkages and stuff.

Can somone give me a link to a water jacket for my motor? I see a johnson one for 3 cyl on iboats store, but not one for chrysler. Will this one work?

Also any tips on adjusting the linkages?