1979 chrysler 70 hp outboard

[wheeler87]

I have had this engine for a while and it sat for about 4 years . this is probably a stupid question but here goes .
I have got the engine running but it doesnt have the power it should . It seems to have low compression in the upper 2 cyl could the rings be stuck to the pistons and can they be free up without removing the pistons or should I just replace them?

 

[eurolarva]

Re: 1979 chrysler 70 hp outboard

Shoot some marvel mystery oil in each of the cylinders and crank the starter and let it sit for a couple of days then try and run it again. Get motor warmed up then do a compression test. Chances are when you winterized it you did not use fogging oil which is cruitial for long term storage.

 

[wheeler87]

Re: 1979 chrysler 70 hp outboard

I will try that first before i Tear it dowm to replace the rings thanks for the input

 

[wheeler87]

Re: 1979 chrysler 70 hp outboard

ok did what you said and one cyl free up but one still hanging up . Put more in and let it sit again?

 

[JUSTINTIME]

Re: 1979 chrysler 70 hp outboard

yes put more in

 

[wheeler87]

Re: 1979 chrysler 70 hp outboard

ok engine has been sitting since my last post with mystery oil in it . Tried again this morning and still no luck . The number 2 cyl still has little compression . any more suggestions . How harmfull would it be to cross the plug wires and try to fire it so it would shock the pistons. could this free it up or would it do more damage than good?

 

[eurolarva]

Re: 1979 chrysler 70 hp outboard

I would take off the exhaust gaskets and see what is happening. Biggest problem with that might be corrosion on the bolts and they may break. Crossing the plug wires is not going to do anything because that cylinder is already getting spark.

 

[roscoe]

Re: 1979 chrysler 70 hp outboard

Did you just let it sit with the oil in it?

Or have you run it since then to heat it up and blow the carbon out?

I would run it and spray a can or Seafoam Deep Creep through the carbs.

I don't think shocking the piston by crossing up the timing will do any good.

 

[wheeler87]

Re: 1979 chrysler 70 hp outboard

I have run the engine for about 20 min and let it cool , then another 20 min . still seems to be hanging up , not as much but still have loss of compression in number 2 . Maybe it just needs to be ran for a while now to see what happens. Can I get sea foam in any marine supply store?

 

[eurolarva]

Re: 1979 chrysler 70 hp outboard

No on the seafoam. Try autozone or NAPA. If you go to a marina powertune is a similar product.

Are you sure the head gasket is not blown? This will also give you bad compression.

 

[wheeler87]

Re: 1979 chrysler 70 hp outboard

The head gasket is brand new .That was the first thing I did when the compression loss was noticed, also had the head checked for warpage at the local machine shop. Will get some sea foam and see what happens . (lets hope that the weather allows a couple more weeks of boating)