mcculloch 4hp aircooled HELP!

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rick101

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Serial # 82090-17114

What year =
spark plug =
fuel mix =

I also did not realize that there is a water pump in the foot that cools? the exhaust lag/housing, does this water reach the bottom of the power head?

This pump is not an impellor rather a rotating bearing, and since I did not realize it was there I ran the motor for quite sometime and revved it pretty high out of water.

Did I hurt the pump?
I was most likely dry since I did not submerge it before running it.

Also this motor runs very loud, there is no muffler on the carburator and the cover that goes infront of the carborator is missing, is this the reason or is this by design?

Hopefully someone can help!!

Thanks
Rick
 

steelespike

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Re: mcculloch 4hp aircooled HELP!

Most would reccomend changing the pump whether you ran it or not.
Be sure its submerged like on a boat and run it see if water mists out the relief holes in the leg.Above the water intakes.Also be sure both are clear
 

rick101

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Re: mcculloch 4hp aircooled HELP!

Yup took it out on the water, and it mists out just fine,.
SO I guess no harm done.

What about the other questions?
 

steelespike

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Re: mcculloch 4hp aircooled HELP!

My aftermarket service manuals carb blow up does not show a carb cover/
muffler..
The motor does have a lower skirt or cover.That may be missing on yours.
Perhaps there is an exhaust leak where the power head meets the leg.
I don't have model year info. My info indicates production 65-69
this in an after market manual that covers 60-72 on other motors.
The 3.5 was also made in 65 and had a air deflector on the carb and was water cooled. with a very similar pump setup.Your motor uses J18Y champion plug set at .035, points set at .020,fuel mix 48:1. about 3ozs per gallon.
 

rick101

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Re: mcculloch 4hp aircooled HELP!

ok thanks for you help.

Maybe there is a leak but Im not sure, very hard to tell. I don't see any smoke if thats what you mean.

At the moment I had a 25:1 mix in there and is doesnt smoke, running a J6J plug. and the collor of the plug is a copper tan.
I guess that is good.

But should I change to 50:1 and that plug you are recommending?
 

steelespike

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Re: mcculloch 4hp aircooled HELP!

I believe it was the Scott Guy(Scott Atwater/McCulloch expert) who was pretty firm about 48:1.not 50:1. Your 25:1 will do no harm if you want to use it up.Actually when it was new McCulloch had established 100:1 using their special 100:1 oil.But that was discontinued.
The J18Y is a different heat range and reach than the J6J.
 

brownest123

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Re: mcculloch 4hp aircooled HELP!

I believe it was the Scott Guy(Scott Atwater/McCulloch expert) who was pretty firm about 48:1.not 50:1. Your 25:1 will do no harm if you want to use it up.Actually when it was new McCulloch had established 100:1 using their special 100:1 oil.But that was discontinued.
The J18Y is a different heat range and reach than the J6J.
Do you have a PDF of the service manual for this vintage.

Thank you.
 

GA_Boater

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Do you have a PDF of the service manual for this vintage.

Thank you.
Steelespike won't be responding for 2 reasons

1) This thread is over 11 years old.
2) Steele hasn't visited in almost 4 years.

Other than that, start a new thread if you want some answers.
 
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