2001 johnson 50 doing my head in

[maxicatch]

Hi guys
i have a maxicat 4.65 with 2 2001 johnson 2 cyl 2smokes on it.
The port engine is giving me brain damage.It does not produce power at wot throttle and will not rev past @2500 in gear.has good compression,swapped out the carbs from other perfect running engine with no effect.has new stator,power pack.sync n link is sweet.prime bulb stays solid and makes no difference if squeezing it while running,tank vents perectly and all fuel lines are new as is pump.VRO has been disconected and running premix.
this motor has been played with by 3 different shops and only gained about 300 revs at wot throttle for their efforts and my expense.

 

[Daviet]

Re: 2001 johnson 50 doing my head in

You didn't say, so I have to ask, what is the compression like?
Will the spark jump a 7/16" air gap, and is it bright blue?

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

Comp is fine, can not remember exact figures but it was identical to starbord engine and i think 3psi different between the 2 cylinders

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

would you believe i have been to every auto parts shop in wollongong(south of sydney) and i can not find a spark gap tester????????
i made one my self out of old drill bits and a piece of timber , is a bit rough but worked well. got a bright blue crack from both leads

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

i have noticed a bit of what looks like exhaust residue(not fuel or clean oil) on the mid section immediately below pan?
Could an exhaust leak be the culprit?
really doey on wot max rpm @2800 rpm and excessive fuel consumption when compared to starboard engine.

 

[tx1961whaler]

Re: 2001 johnson 50 doing my head in

It will run crappy with an exhaust leak. Try running it with the hood off and see if it perks up.

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

cheers tx1961whaler
ok tried running with cowl off and it mad no difference.
a mate has suggested reeds???
What would be the symptom of worn out reeds?
i pulled the carbs off and for what i can see they look fine.

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

well i had a fiddle with the motors today and i noticed that when i spin the fly wheell foward and back on the good engine i could hear the vacume and pressure moving the reeds in both directions but on the bad mot only could hear it when i turned the flywheel clockwise.
i whipped of the carbs and leaf plate assy and a couple of the reeds were not seating proparly and on one of the reed cages it has a little nick beside the leaf plate, it is not very big,about the size of a match head but i can see daylight through it.
Could this be my problem??????????
Any input would be great guys.
Cheers.

 

[boobie]

Re: 2001 johnson 50 doing my head in

Yes......

 

[maxicatch]

Re: 2001 johnson 50 doing my head in

cheers boobie.
luckily i can remove the cages from the starboard engine and fit to port so i can test it out.hopefully the thing will sing.
disappointing though,this motor has been checked over and apparently fixed 3 times by the local omc guys.