85 HP Chrysler loss of power/low RPM

[jombee]

My 1979 85HP Chrysler outboard on my Bassrunner has been running great for years. Last week about 3 minutes after getting up on plane at WOT at the normal 5500 RPM the engine started losing power. It will now not idle without giving it gas (RPM's at about 1,500) and when running on water and it wont get over 2500-3000 RPM

I changed the plugs, new gas lines, primer bulb, fuel filter, fuel/water separator but nothing improved at all. I am getting a spark to all cylinders and the primer bulb gets firm just fine. I'm not sure about compression, and I don't have equipment to test it.

I'm a bit of a novice, can someone please let me know the best next steps in order for troubleshooting this issue?

Thank you!

 

[jerryjerry05]

Most auto parts stores loan comp testers.
Just make sure you remove all the plugs when doing the test.
Jump the motor at the solenoid, don't use the key.
Check spark on all 3 cyl.
What ignition do you have? Magnapower?

 

[jombee]

Hi Jerry, thanks for replying!

I've got the compression tester from a auto parts store, but do not know what you mean by "jump the motor at the solenoid". Can you please explain or point me to a tread with instructions? (I checked youtube, etc. and could only find information for autos). I'm not sure about the ignition, where would I check this?

Thanks again for your help, it is greatly appreciated!

 

[jerryjerry05]

Post some pics of the ignition system.

The battery cable goes through the cover, it hits the solenoid first.
The solenoid has 2 BIG lugs and 2 tiny lugs.
One tiny is the ground and the other is for the starting.
If you supply 12v to the tiny lug it will make the motor turn over.
Keep the key off.

Then do the comp test.
Google comp tests.

 

[jombee]

Thanks Jerry!

I understand and will run this test tomorrow. I've got a manual showing me the proper rating and I know what it was 3 years ago when last tested. I will post a pic of the ignition system tomorrow also

Thanks again for all of your help!

 

[jombee]

Hi Jerry

I wasn't able to crank the engine using the solenoid method you described, all I heard was clicking.

When I cranked the engine using the key I got the reading below

cylinder 1 (top) 120 PSI
cylinder 2 (middle) 115 PSI
cylinder 3 (bottom) 45 PSI

SELOC says the compression should be 150-165

When I bought the boat 3 Years ago I was told the compression was:

cylinder 1 (top) 130 PSI
cylinder 2 (middle) 125 PSI
cylinder 3 (bottom)125 PSI

Assuming doing this test with the key at least gives somewhat reasonable results, it sure seems like my problem is cylinder 3

How do you think I should proceed?

Thanks again for your help!

 

[jombee]

Update

I removed the cylinder head to inspect inside, and found that the head gasket had a break at the very bottom at cylinder 3 (picture attached)

I've ordered a replacement gasket and really hope this was my issue.

 

[jerryjerry05]

The first thing you do is stop believing what Seloc /Clymer manuals say.

What your looking for in compression results is that all cyl. are real close.

The difference in testers can send a guy into a panic, thinking his motor needs repairing on all 3 cyl.

The actual results should read 145-160#
But not all gauges read the same.

My neighbor gave me a Harbor Freight gauge.
It read 125# on my 85hp. 3 cyl.
My Mac tools gauge read 150# all 3.

Whats good is that the results are even, different on both gauges but even.

That hole in your gasket? I bet a new one fixes your problem.

 

[jombee]

I hope so Jerry!

3 quick questions

Should I use any gasket sealer/spray on the new gasket? If so, what brand would be best?

What is the best method/stuff to use for cleaning off some small stuck on pieces of the old gasket?

SELOC says the head bolts should be 225 in lb, is that accurate?

Thanks again for all of your help!

 

[jerryjerry05]

No sealer. It's already on the new gasket.

I use the green scotch bright pads or a wire wheel on a die grinder.
Just don't dig too deep with the wire wheel.

They got that one right.
It equals 18#
Tuorqe them in 3 steps.
First at 13# then again at 15# then 18#
Remember to stagger the pattern.

After 5 -8 hrs. re-tuorqed.

The bolts, clean and lube them when reinstalling.
Also clean the threads in the head.
NO anti-seize if it gets used in salt water.

 

[jombee]

Thank you very much Jerry!

I really appreciate your help with this!

 

[Redbarron%%]

I think your original problem is with a bad fuel pump.
especially not, perhaps, picking up fuel at low rpm

 

[jerryjerry05]

Redbarron, did you read the whole post?
He posted a pic with a hole in the head gasket.

 

[Redbarron%%]

Original problem still sounded like fuel pump.
When he gets it back together I would bet he still needs to rebuild the pump

 

[jombee]

Update

The new head gasket is installed and the motor runs great again!

Thanks again for all of your help Jerry!