No Spark 1976 Chrysler 70 HP

[joshstan1978]

New to boat ownership. Me and my 11 year old son fish 2-3 times a week and recently acquired a 1977 muskie 550 with a 1976 Chrysler 70 hp motor. Took it out 2-3 times and ran great! Carbs got stuck with gunk but I got them all cleaned up and put it in the water. However, she kept dying 50 yards from the dock. Took it in and the mechanic said there is no spark. He doesn't want to work on it because parts are old and there is "no literature".

Anyway, I was wondering were would you guys start? Is it worth trying to salvage? It's got great compression, but I don't do any electrical work, I don't even have a multimeter? Would love to revive this boat motor as I cant afford a different boat, but can't get anyone to fix a motor this old.

Thoughts?

 

[Nordin]

Three things are needed for an engine to run.
Spark, compression and fuel.

You says you cleaned the carbs, then you have to check for spark and compression.
Compression should be about 130-150 PSI but can be lower, but it is important it is even and not so big different.
10-15 % in difference is acceptable. About 100 PSI and up is accetable with max 10-15% in different.

Check for spark is easy, remove all plus and ground them.
Run the starter and check the spark at each plug.

Sounds odd the engine does not run after a carb cleaning.

Do not trust pro mechanics, they want to sell new engines and they do not know about the older stuff.

These Chryslers are good engines and easy to work on, simply old school design.

 

[Tassie 1]

No spark could be a few things,
distributor/points
" "/ preampifer
timing probs
CD unit has failed,

all electrical in other words,
there is a ignition troubleshooting site that l keep forgetting the name off that has your system on it,

they are fairly simple motors to work on but are getting on a bit now

good to see nordin back.

 

[Redbarron%%]

I rebuilt my carbs on my sport jet and then no spark.
It took a while to find the that I had turned the deadman switch off

 

[Tassie 1]

Where is the " deadman " switch on a '76 Chrysler?

 

[jerryjerry05]

No deadman switch on older Chryslers.

70hp??? no 70's made in 76???
Made in 79-80
Just making sure we know what were working on??

You'll need to get a multimeter to do the basic tests.
outboardignitiondotcom will help you troubleshoot your motor.

Like Nordin (welcome back)suggested, compression and spark test.

Did you test the overheat system?

There are a bunch of things that can go wrong but usually it's not that hard to figure them out.

 

[joshstan1978]

I looked up the year using an ID tag I found. I will post that and more info next week when I pick it up. I could have sworn it was a 1976 70 HP.

mechanic said compression was basically 140 on all the cylinders.

 

[Redbarron%%]

The first thing I would look at is the fuel delivery.
If the engine will run at idle and quit 50 yards from the dock.
I assume that this is not a no spark issue.
The MECHANIC said there is no spark, but he didn't want to work on it so I might question that.
Check for spark with an induction timing light at cranking speed.
Personally I think that if it started and then quit the ignition might be OK.
Plugged filters (if present) and bad fuel pump come to mind.
If I am correct that the engine start and then quits put a fuel pressure gauge in the line to the carbs, and if there is a filter, change it.
If there is no filter add one.
Often water in the fuel will make this problem worse and a clear filter will at least let you see how dirty the fuel might be.
A filter between the pump and carbs would be a good idea to keep pieces of a bad pump from getting into the carbs and causing problems there.

 

[Nordin]

Information about the year model.
Chrysler made 70Hp from 1969 and up till 1973.
Then it came back in 1979 and 1980.

 

[Isa4325]

No deadman switch on older Chryslers.

70hp??? no 70's made in 76???
Made in 79-80
Just making sure we know what were working on??

You'll need to get a multimeter to do the basic tests.
outboardignitiondotcom will help you troubleshoot your motor.

Like Nordin (welcome back)suggested, compression and spark test.

Did you test the overheat system?

There are a bunch of things that can go wrong but usually it's not that hard to figure them out.

Jerry I own a 1972 Chrysler 70HP 707HE and it does have a cut off switch mounted on top of the distributor.

 

[Nordin]

Isa the deadman switch Jerry talks about is a switch that cut the ignition of if you fall overboard.

The switch you are talking about is the neutral switch whitch cut of the starter solenoid if the gear shifter not is in neutral when starting the engine.