Logo
FULL SITE MENU

Chrysler 70hp 1975? start issue

F

Firefly_Sweden

New member
Hi all clever people out there try to help me solve my starting issues please...

Problem is that flywheel will turn fast for half a turn then almost stop and so on.

I have checked battery with battery tester OK
All connections cleaned
Compression on cyl.1 (95psi) cyl.2 (123psi) cyl.3 (105psi)
Starter draws 20 amp with no load and 300amp with load.
Timing also checked but can´t see why that should be cousing this problem.
With plugs out flywheel spins...

Thanks!
 
The compression is WAY off???
How are you doing the test?
Remove all the plugs and jump at the solenoid.

Low comp can cause the hard turning.
 
Hi
I tested last night to jump the starter and flywheel spins better so now i think it is the solenoid that is broken. I measured amp and when flywheel spin i have 160amp. 300amp at startup.

Br
 
All connections cleaned almost new cables
Battery is load tested
Tested comp with all plugs out and used starter proberly with a bad solenoid. So i will redo the comp test and jump the starter so i bypass the solenoid. I will test to do a wet test aswell in Case of faulty rings or valves.
I have also done a leak down test and it seems to be in good condition about 15% loss of pressure. And in the green zone on my instrument on all 3 cylinders. But noticed that i had to hold flywheel on cylinder 3 because the cylinder wanted to go down.
 
Do the comp tests with a different gauge.

The comp needs to be within 5# of each other.
They can all be 80# but need to be real close.
If they are 80 the low results are probably a bad gauge.

Retake the tests and let it turn over at least 5-7 times or more.
 
I did a new comp test today with battery direct to starter and i had 125psi in cyl 1 105psi on cyl 2 and 100psi on cylinder 3. The gauge is new and are not leaking.

I also did a wet comp test and now all cylinders are showing 125psi so i have some worn pistonhead rings but i dont think thats the real problem it worked good enough last year. Sure the rings could get stuck over the winter...
 
Comp testers and the results vary.

Sold a 2002 Mercury 225 EFI
The prospective owner brought a brand new gauge from Harbor Freight(cheapo tools)
The first cyl. read 85 as did the second.
It's supposed to be 150#

I stopped him and got my tool.
Hooked it up and got 150# on all 6 cyl.
My tester was new in 1987 and cost 160$ then.

Did you rebuild the starter?
A brush and spring set is fairly cheap.
 
Picture 006.jpgPicture 004.jpgPicture 001.jpgPicture 008.jpg

These pics are from a working but dragging starter.
The springs show excessive heat from turning over.

The piece where the springs and brushes sets can short out.
The grit from the burned brushes filters down and can cause a drain.

The 5/16 screws(2) come out and the part gets wire brushed and I even wash them
with detergent. I use Dawn soap.
Undo the battery lead and clean that too.
 
Back
Top