Bottom Cylinder Fuel Issue 50HP JOHNNY

[thouse]

Hello,

Well I have solved my spark issue , now I have a fuel issue.
Motor has 110 PSI TOP , 125 BOTTOM COMPRESSION
Rebuilt carbs/Fuel Pump
New Powerpack , Rectifer
Motor starts and runs
Drop test reveals TOP cylinder running only (110psi)
50:1 mx in a bottle sprayed into carb/cylinder causes motor to perk up when sprayed and while running on TOP cylinder
With top plug disconnected, I can get motor to run on bottom cylinder by feathering the choke plate manually. It has to be just barely open. Seems like it is not getting enough fuel.
I have cleaned carbs and am at a loss....primer bulb gets hard before starting , while running it gets soft.
Adjustments on low speed jet make no difference as I cant keep it running long enough to adjust it. Again, will only run with feathering and manipulating the choke...

Any thoughts/ideas? Thanks!

 

[Bosunsmate]

Swap your carbs over,
If the problem is still the bottom carb, suspect lower crank seal has gone,
I suggest you post engine year too

 

[Faztbullet]

Fuel restriction to/in carb. Check to see if blockage in fuel tee to lower carb,hose swollen shut internally, trash under seat, needle tip swollen or float hung or installed upside down...

 

[thouse]

I didn't think you could switch carbs around? Motor is a 1972.

 

[thouse]

There is a spring inside the crankcase hose to fuel pump is this normal? Would a faulty fuel pump cause fuel to go to top carb (that is where fuel pump line goes to then gets fed down to bottom carb) and not have enough "pump" to get fuel down to bottom carb? Should blowing into fuel pump crankcase hose cause fuel to flow or does it operate on suction? thanks

 

[Bosunsmate]

I didn't think you could switch carbs around? Motor is a 1972.

Maybe not on a 72, I can on my 1982 which dates back to like 77/78 model

 

[Bosunsmate]

There is a spring inside the crankcase hose to fuel pump is this normal? Would a faulty fuel pump cause fuel to go to top carb (that is where fuel pump line goes to then gets fed down to bottom carb) and not have enough "pump" to get fuel down to bottom carb? Should blowing into fuel pump crankcase hose cause fuel to flow or does it operate on suction? thanks

I think its blowing and sucking as the crankcase goes from vacuum condition to compression(positive pressure)
Try grounding the bottom sparkplug and run the motor for a few turns, see if that bottom plugs wet

 

[thouse]

plug is somewhat dry. Only will run on that cylinder if i manually play with the choke plate to get fuel into it. Or , if i spray fuel into carb it will perk up.

 

[Bosunsmate]

Why do you think you cant swap the carbs on that motor?
Id say its either that or the lower seal.
Bang some oil into that cylinder while your at it