Neptune Mighty Mite 1A39

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Ronstoys1

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I recently purchased a Neptune Mighty Mite 1A39. I in the process of getting it to run. I checked the spark today, it was strong, took a compression check and had 32psi. I was told by a mechanic that I need 60psi in order to start it. Can anyone tell me if that's true ... do I need 60psi in order to start.
Thanks to anyone that can help. Ron
 
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tmcalavy

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Re: Neptune Mighty Mite 1A39

Might be worth a third check, to save yourself some frustration. That is only half of what is considered normal. If it does only have 32psi compression, it will be hard to start and won't run right at slow/idle speed...and will run erratically when you throttle up. Might try some PB Blaster or Sea Foam in the cylinder, overnight soak, to seek if that will free up the ring on the cylinder...that could be broken, if it isn't stuck.
 
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Ronstoys1

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Re: Neptune Mighty Mite 1A39

To tmcalavy ... I wil get som PB Blaster Friday and try over the weekend. I will let you know. Thanks for trying to help me. Please keep up with my thread, I may need your help. Thanks, Ron
 
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Tom @ Buzzard Bluff

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Re: Neptune Mighty Mite 1A39

Doug Penn <http://www.youtube.com/watch?v=g0hvbR1aVCE> is the Neptune man. He bought up all remaining parts and stock when they closed the doors so he is not only THE source for knowledge but parts as well. He might even have a serviceable powerhead if you're determined to resurrect it from the dead. (32 PSI compression is dead unless soaking it frees sticky rings! Personally I'd soak it in Seafoam)
 
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steelespike

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Re: Neptune Mighty Mite 1A39

Have you squirted some oil in the plug hole and does it raise the compression?
As suggested a good soak with sea foam may free things up.Be sure the piston is covering the intake and exhaust ports.I believe it has a metal ,loose clearance, impeller so no worries for a short dry test.I had one with a shortened stroke from
from messing with a badly worn rod bearing.It wouldn't run in the water but
would dry. Ended making a lamp of it.
If you crankit with the plugs out you may here the puck-puck sound of crankcase pressure. may give you an idea if cranck seals are any good.
Any stray oil under the flywheel may indicate a weak upper seal.
 
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F_R

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Re: Neptune Mighty Mite 1A39

Aw heck, it probably has a blown head gasket.
 
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Ronstoys1

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Re: Neptune Mighty Mite 1A39

tmcalavy said:
Might be worth a third check, to save yourself some frustration. That is only half of what is considered normal. If it does only have 32psi compression, it will be hard to start and won't run right at slow/idle speed...and will run erratically when you throttle up. Might try some PB Blaster or Sea Foam in the cylinder, overnight soak, to seek if that will free up the ring on the cylinder...that could be broken, if it isn't stuck.
Click to expand...

I did the PB Blast and bought some Seafoam yesterday, I'm going to let it set overnight. I have a question should I leave the motor upright for the soak?
 
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Tom @ Buzzard Bluff

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Re: Neptune Mighty Mite 1A39

Ronstoys1 said:
I did the PB Blast and bought some Seafoam yesterday, I'm going to let it set overnight. I have a question should I leave the motor upright for the soak?
Click to expand...

No. Turn it so the cylinder is upright. Turn the flywheel to get the piston near TDC so the ports are all closed and then fill the remaining space with the Seafoam. If you're in no rush repeat the Seafoam fill every night until you have time to fool with it. By then you'll probably have the crankcase full of Seafoam which must be drained before proceeding. Best way is to pull the carb and reedblock (if it has one!) and drain it in the same orientation as when you were soaking.
 
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