Chrysler 70 hp starter not working under load

[Dadio]

I am trying to get a compression check on the cylinders of my Chrysler but having other issues. First, I have a brand new starting battery 625 starting amps measures 12.63 volts. Brand new starter measures 11.25 volts when cranking (not installed) installed measures 2.5 volts when cranking. I have cleaned and tightened all connections, checked for good ground. Here is the problem, when cranking with no plugs in starter turns over engine rapidly but when I put a plug in, it slows and stops and if I keep the battery attached, it will slowly rollover another compression stroke. Jumped the starter eliminating the solenoid same result; jumped solenoid from battery side to start terminal on solenoid, same result. Took battery off and cranked it measured volts at 11.25 while cranking. solenoid is working starter is working, but engine will not rollover enough to start or check compression. Basic troubleshooting is done, bad ground, poor or loose cable connections, bad battery, bad starter all eliminated as issues but problem persists. Does anyone have any experience with this problem? I've seen threads with the same problem but no one seems to have the answer. Hope someone can point me in the right direction...

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load

New starter can be bad.Try taking it apart???
Doing a comp test.
Remove the plugs to do this.
Use a jumper wire,key OFF.
Remove the plugs,throttle all the way in forward.
Install tester,turn over till guage stops going up,usually 5-6 rotations.
Repeat on the other cylinders.

Profile,location? You might be close to someone who can help???

 

[stubtail]

Re: Chrysler 70 hp starter not working under load

When you "jumped", did you utilize jumper cables, or reconnect existing wiring? Just trying to eliminate faulty wiring, even though you indicate that connections are clean and tight (crimped terminals under heat shrink can be troublesome).

 

[Eazzy]

Re: Chrysler 70 hp starter not working under load

Had the same problem on a 75hp. bought a new starter off Ebay for $65.00 still had same problem wouldn't crank fast enough turned out to be the new starter was a piece of junk. Rebuilt the old starter haven't had the problem sense.

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

Yes, if I could get the motor to spin I could do that.

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

When you say you re-built the old starter, what did you do? Replace brushes, anything else? Don't have the old starter seller had installed new starter. Now I'm thinking since the starter bench tests good and with a severe voltage drop under load, (2.5 volts cranking should be 11.5) it maybe a starter for a much smaller motor. What do you think?

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

Ok, updated my profile...

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load

You try the comp test??

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

You try the comp test??

Not sure what that is. Please explain.

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load

Compression test.
Without good comp on both cylinders it can be hard to turn over.
Make sure you remove all plugs when testing.

 

[Eazzy]

Re: Chrysler 70 hp starter not working under load

Had the same problem on a 75hp. bought a new starter off Ebay for $65.00 still had same problem wouldn't crank fast enough turned out to be the new starter was a piece of junk. Rebuilt the old starter haven't had the problem sense.

New brushes and springs cleaned and oiled bushings. The new starter worked good on the bench but when you put a load on it just didn't have enough power to turn over grandmas wheelchair on a down hill slope.

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

Compression test.
Without good comp on both cylinders it can be hard to turn over.
Make sure you remove all plugs when testing.

That's what I'm trying to do but won't sprin fast enough to register compression. Took all three plugs out and spins great but put compression tester in and won't roll over.

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

New brushes and springs cleaned and oiled bushings. The new starter worked good on the bench but when you put a load on it just didn't have enough power to turn over grandmas wheelchair on a down hill slope.

Sounds like my problem. Now looking for new starter see if it solves th problem.

 

[Eazzy]

Re: Chrysler 70 hp starter not working under load

Might try and find someone that has used one that they know is good that you can try before purchasing a new one. a starter rebuild shop might be able to put a load on the old one and run a test . jerryjerry05 is pretty up on that more than i You can purchase a brush kit here on iboats it's a lot cheeper than a new starter.

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load


Depending on the starter(your motor a 79/80?)they are real easy to take apart.
Usually no power from a starter,the brushes are stuck or the magnet has come loose.
Maybe the main connection is grounded out.

Now make sure the connections are all tight.
The ground on the engine block.
Then make sure the cable is solid,no mushy or swelled spots,no loose or soft wires at the connectors.
First pic is the tool I made to install the brushes,might not work on your starter,maybe it will??
The rest are from a supposedly GOOD starter.

 

[Eazzy]

Re: Chrysler 70 hp starter not working under load

View attachment 165534View attachment 165535View attachment 165536View attachment 165537View attachment 165538
depending on the starter(your motor a 79/80?)they are real easy to take apart.
Usually no power from a starter,the brushes are stuck or the magnet has come loose.
Maybe the main connection is grounded out.

Now make sure the connections are all tight.
The ground on the engine block.
Then make sure the cable is solid,no mushy or swelled spots,no loose or soft wires at the connectors.
First pic is the tool i made to install the brushes,might not work on your starter,maybe it will??
The rest are from a supposedly good starter.

there ya go JJ05 i used one of the wife's old spatulas as a brush tool

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

Might try and find someone that has used one that they know is good that you can try before purchasing a new one. a starter rebuild shop might be able to put a load on the old one and run a test . jerryjerry05 is pretty up on that more than i You can purchase a brush kit here on iboats it's a lot cheeper than a new starter.

Got a new starter same problem. I don't know if this makes any difference but motor is on motor stand and not on boat or connected to controls. Engine manual tests for silenoid and it is good, "clicks" when energized and output is 11.9 volts. I think I'm still not getting enough volts to starter. Manual says about cranking slowly, cables to long. Since I'm using jumper cables, I do notice they are getting really warm after trying to crank engine. I don't think they are any longer than the cables in the boat. BTW, the engine is a 1969 and was stored in a barn for 30+ years. Goes with a one of a kind 1957 wooden boat I'm restoring.

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load

JUMPER CABLES????? NO wonder it aint turning?????
Probably cheap ones TOO!!!
Gotta use at least a #4 guage wire.

Most jumper cables are an 8 even a 10.

 

[Dadio]

Re: Chrysler 70 hp starter not working under load

Well time to close this thread, JJ05 was right on. Jumper cables were replaced with shorter heavy duty cables and started cranking right away. Thought it was coming right off the engine stand. Compression tests 140 in each of the three cylinders. I'm a happy camper. Going to open a new thread for help in why there isn't any spark.
Thanks for all the comments, very helpful. BTW, anyone need a starter?

 

[jerryjerry05]

Re: Chrysler 70 hp starter not working under load

No,but I see your in Michigan,
You can send me some venison!!!