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Johnson JW21 Hard to start

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randall_b

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"Hello all. Looking for some h

"Hello all. Looking for some help on a rough to start Johnson 3hp light twin. Have invested over $225 in parts to get this thing back in shape. (i know that is alot for a 1966) Runs ok when I can get her going but starting is rough. Tank and screen are clean. carb was rebuilt, entire ignition system replaced, coils, condensors, points. New rings gaskets, water pump....etc...
All I can think of at this point is replacing the reeds but I can not find a part number to save my life. Dealer is NO HELP on a motor this old. Any advice or part numbers would be appreciated."
 
"those reeds,are broken down i

"those reeds,are broken down into sev pieces--Unless it is spitting back thru carb,u prob dont have a reed valve prob,unless maybe they are sticking...in that case,use some de-carb on them,or remove a carefully clean.also,it is poss to have intermal suction going on between the 2 cyl's,due to age,causes hard starting rough idle etc,but this is rare as well.did u gap the points at--.020--?...are they very clean?"
 
"Yes points are brand new, set

"Yes points are brand new, set to .020.
I am a bit confused by the suction between cylinders? how would you diagnose and fix?
The reason I was leaning towards the reeds because I had trouble getting them to lay flat against the reed block as a natural position.
They seem to rest with about a .015 clearance."
 
If the center main bearing is

If the center main bearing is worn then the upper cylinder can suck air thru it from the bottom cylinder.Or in other words not enough air is drawn thru the carburetor.Also if the joint surfaces on the cylinder block and crankcase cover are not meticulously prepared you can have an air leak between cylinders.
 
"ok,
scoped in the cylinder,

"ok,
scoped in the cylinder, no evience of leak.
Where can I find Reed part numbers and or parts. I do not think they should be sitting proud .015". Can not seem to get them to lay flat."
 
I think if you went to the BRP

I think if you went to the BRP web site you would find that reeds on the 68 JW are the same.
 
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