1975 Chrysler ran GLORIOUSLY! Suddenly it shakes violently and won't start.

[bangshift440rt]

1975 CDI Ignition Chysler 55hp. Here's the background: First time boat owner, took it out yesterday, fired right up, ran up and down the river and out into Green Bay a little bit. NO ISSUES at all. Today, the key switch refused to turn the engine over so I assumed dead battery. Battery was not dead. Jumped the ignition solenoid, tried the key again and the key worked to start the engine just like yesterday. So the boat starts up beautifully, I keep it a little bit revved for a minute or so as it's warming up. I go to put it in reverse and it stalls out and shudders. No big deal right? WRONG! Put the boat back into neutral and try to start, it fires on occasion and VIOLENTLY rips the steering wheel back and forth and causes the entire boat to shudder. I assumed fouled plugs so I pulled them, they were wet. I replaced with some brand new spares. tried to start, SAME EXACT THING. It looks like the engine is trying to rotate the wrong direction when it fires! So I get the boat home, put BRAND NEW plug wire in it, took out the brand new but WET spark plugs, cleaned and dried them, replaced everything, squirted some ether, and sure enough, every time it fires the entire boat seems like it's going to twist apart and crack. Could the ignition timing have somehow slipped when I put the boat in reverse? The reason for the ether was because I figured if the gas SOMEHOW got water in it, it would at least start for a minute so I could eliminate the ignition system as the culprit. Thanks for any help!

 

[Frank Acampora]

First, eliminate the lower unit as a cause. Drop the lower unit and start the engine. If it no longer vibrates, you have trashed the lower unit gears. If it still vibrates, then look at electrical.

It would help to know if this is a single carb 55 or a dual carb 55. It would also help to know--if it is a dual carb-- if it has Magna-Power II ignition. I don't know if Chrysler made Mag II ignition as early as 1975 but it is worth asking.

 

[bangshift440rt]

It has a single carburetor. It doesn't start period to even know if it vibrates, it just bucks backwards so hard when it tries to fire that the boat shakes. when i pulled the plugs, i spun the engine over for a little bit to get any excess gas out of the cylinders, thinking it was just flooded. there was no shaking or vibration of any kind with the engine spinning freely in neutral. So assuming it's electrical, what is the physical part that could be causing this do ya think?

 

[Frank Acampora]

Now, I don't remember exactly which ignition system it has so take this as only a possibility. IF the engine has a CD system that also uses points, it is possible that the flywheel locating key has broken. the cam would have shifted, putting the timing in the wrong place, making the engine want to start backwards. SO: Remove the flywheel and check to see that the key is either broken or intact.

To do this, borrow or rent a steering wheel puller or a harmonic balancer puller. Remove the center nut. Screw in three 1/4 X 20 bolts into the top of the flywheel and after tightening the puller, rap the center bolt a couple of sharp blows.. When reinstalling the flywheel, tighten the center nut to 95 foot pounds. too loose and it will snap the key.

 

[Frank Acampora]

Now, I don't remember exactly which ignition system it has so take this as only a possibility. IF the engine has a CD system that also uses points, it is possible that the flywheel locating key has broken. the cam would have shifted, putting the timing in the wrong place, making the engine want to start backwards. SO: Remove the flywheel and check to see that the key is either broken or intact. Suffice to say: If the flywheel has a top dead center mark and it does not line up with the block pointer with the top piston at top dead center, then the key is broken and the flywheel has shifted position.

To do this, borrow or rent a steering wheel puller or a harmonic balancer puller. Remove the center nut. Screw in three 1/4 X 20 bolts into the top of the flywheel and after tightening the puller, rap the center bolt a couple of sharp blows.. When reinstalling the flywheel, tighten the center nut to 95 foot pounds. too loose and it will snap the key.

 

[bangshift440rt]

Thanks! Once I get the tools I'll check it out and let you know how it went.

 

[bangshift440rt]

Thanks! Once I get the tools I'll check it out and let you know how it went.

 

[bangshift440rt]

What is the purpose of the spark control link and the spark control bearing? Does it retard the ignition for starting?

 

[Frank Acampora]

These engines have a very simple mechanical spark advance. The timing is fully retarded at idle and full advance will be somewhere around 30 degrees. Typically there is a stop in neutral so the timing can be advanced a couple of degrees for cold starts.The link attaches the timing tower to the carrier plate under the flywheel or in the case of some electronic ignitions, the trigger.The timing tower controls the advance through the speed control cable and also synchronizes the opening of the carb(s) to the timing advance.

Not sure what you mean by spark control bearing. There IS a brass bearing on the carrier plate which prevents wear under constant throttle changes and ensures consistent point settings.

 

[bangshift440rt]

Alright, the verdict is in. Got the flywheel off, and the flywheel key was sheered off and everything had rotated a good 45 degrees from where it should be. Before I pulled the flywheel, I put the pistons each at TDC and the timing mark was nowhere near where it should be so I knew for sure what happened. Where can I get a flywheel key quickly? maybe a points set too while I'm at it..

 

[bangshift440rt]

Just ordered one from Ebay. Gonna go clean everything up under there now.

 

[Nordin]

Before you mount the new flywheelkey, lap the crankshaft tap and the flywheel with Carbo Rundum (grindinggrease compound) which you use when laping regular carvalves (four stroke).
Apply a small amount of Carbo Rundum at the tap, put the flywheel on and rotate the flywheel about 90 dgr each time. Put a little amount of force at the wheel while rotating.
Move the wheel about 90 dgr and repeat the rotate. Do this a hole 360 dgr turn and then clean the tap and the flywheel surface. It should be clean and have a grey look.

Mount the key and torque the flywheel to proper value, About 100Nm (80 ft lb) I think.

 

[bangshift440rt]

Well folks, got everything back together correctly and it fired up the first revolution! Thanks for the tips. I lapped it in good and even put some locktite on the flywheel nut.

 

[foodfisher]

I just can't beat the feeling of beating a problem. Kuddos to you and the help.