compression leak down ?

[1960-lonestar]

hey guys i just re check my compression just to double check that its still sits around 165 per cylinder and yes they are thank god , anyways , for a two stroke is it normal for the cylinder to leak down as soon as your done cranking it over , it holds for a second or so then down it goes, i get a good reading but they dont hold they leak right down steadily so is this normal for two strokes since theres no valves to deal with? i cant remember if there is a difference between the two types of engines, and when i turn it bye the fly wheel bye hand it turns over pretty easly with some resistance but no kick back compression so am i thinking head gasket possible here? thanks for your replys ,

 

[P 0 P E Y E]

Re: compression leak down ?

You performed a compression test and all cylinders are with in 10 psi of each other or less?

Is there a problem starting or running this engine?

Please provide more information when you can.

Thanks

 

[1960-lonestar]

Re: compression leak down ?

i have had it out on the water three times now and it starts right up with new plugs in it and ran fine all day but the next time i took it out it ran just like it did the first run, it fires up and takes of like normal with some fenessing to get it out of the cold start up mode but once running it runs fine but after a good day out on the water coming back to port in the no wake zone idleing along it will eventually stall out and be alittle dificult to restart but it does and you have to keep it up at a higher idle and then it still eventually dies anyways , and when were out fishing one time fires right up another like its cold fould
,? tashasdady says it sounds like a carb rebuild time and i had my hunches, but my new question was compression leak down is it normal to leak down on both cylinders, there both even compression wise and leakdown wise, and the flywheel isnt really hard to flip around pass a compression stroke with a medium to slight resistance, ios this a head gasket issue ? and not a carb rebuild issue , but it doesnt give me any good indacators of what the probly might be, thanks for your replys , greatly apreciated

 

[R.Johnson]

Re: compression leak down ?

I'm not quite clear .on what your asking here, but I know that on a leak-down test,the guage will drop to zero very rapidly when the pressure is shut off. That small volume of air is going drop quite fast just around the ring gap's.

 

[1960-lonestar]

Re: compression leak down ?

ok if you do a compression test is it supposed to hold at 165 and stay holding at that reading , or is it supposed to slowly leak down with out releasing the pressure? and if it does leak down is it normal?or is there a head gasket issue possibly
i know when ive done a motor with valves they tend to hold pressure but since it a two stroke does it act different? thanks again for your replys guys,

 

[jonesg]

Re: compression leak down ?

he just answered that quesion.

 

[1960-lonestar]

Re: compression leak down ?

ok thanks , i didnt read it correctly the first time now it make sence , thanks guys your great, im an auto mechanic trying to learn outboard quirks and stuff , i own a 1960 -lonstar cuddy 17 ft that i am converting into a columbia river boat in s/w washington, its powerd bye a 1985 60 hp johnson tnt that has great possiblities of beeing a good motor for this boat, so far it rides like a dream just a few running issues , and thanks to you guys money will be spent in all the right ereas , thanks again great advice,