Problems with dual line conversion

[racerone]

Many , many years ago when I worked at a Johnson dealer I heard face to face,------" thank you young man , for explaining "

 

[BlackoutBill21]

Well I plan on checking everything so that ebay pump is on the way... in the meantime I’ll try holding the tank above the motor, and the tank is indeed vented. I will also if all else fails check my conversion... I find it hard to figure out how I messed up both methods but I am new at this so we will check it! Assume nothing after all.

also I’ll recheck my carb but I remember setting the float level correctly

 

[Crosbyman]

holding the tank above the pump will siphon gas down and only confirm what you know already ...fuel delivery is failing

you did remove the small check valve behind the carb on the blocked channel method ?

check fuel pick-up in the tank for obstruction (crud) or try a different tank/hose


last resort…


you can always plug the pressure nipple shut

mount a plate on a side cover or drill l and tap the cover install a nipple and retry

 

[BlackoutBill21]

Yeah I know the plate method... I just don’t want to drill tap buy a nipple and fit it to a pump... not yet anyway... yeah I took the check valves out

and I’ve used 2 different tank setups same result

 

[Crosbyman]

never happen to me but I heard some folks had issues with crankcase sludge/oil residues working itself in the pulse line

on 2 line hose it is not an issue since the juice ends up in the pressure tank but....juice in a pulse line it may cause problems who knows

normally that stuff goes out the crankcase drain valve … maybe yours are in need of a check up

you can install clear pulse and fuel lines to see what is going on at high speed fuel flow wise and crud in the pulse lines

maybe your crankcase pressure is weak due to bad lower seals ???

 

[BlackoutBill21]

never happen to me but I heard some folks had issues with crankcase sludge/oil residues working itself in the pulse line

on 2 line hose it is not an issue since the juice ends up in the pressure tank but....juice in a pulse line it may cause problems who knows

normally that stuff goes out the crankcase drain valve … maybe yours are in need of a check up

you can install clear pulse and fuel lines to see what is going on at high speed fuel flow wise and crud in the pulse lines

maybe your crankcase pressure is weak due to bad lower seals ???

Thats an interesting observation! I would hate to take the power head back off to reseal the lower unit but I might just because why not!!

interesting side note / update. The first motor i referenced was never on the boat. Took it out as a back up because if my main motor dies at least i can troll/ go slow back to shore.

THING RAN FLAWLESSLY! So maybe the smoke/ barrel water just not providing adequate back pressure? Thats my guess!

Going to try The second motor on the water to see if that what it was! If that doesn't work Im going to reseal the lower unit!

Thanks for the help Gents. Ill post what the verdict was with the second motor.

 

[F_R]

????How did the lower unit enter the conversation? If you are thinking "crankcase" he was referring to the engine crankcase.

 

[BlackoutBill21]

????How did the lower unit enter the conversation? If you are thinking "crankcase" he was referring to the engine crankcase.

YES! Im sorry. He said lower seals not lower UNIT seals. The lower crank seals were replaced when I took the powerhead off to change the water pump!
Sorry again

 

[oldboat1]

Those pressure tank systems sure cause problems.

 

[BlackoutBill21]

Those pressure tank systems sure cause problems.

lol I see what you're getting at. I convert it so I can sell it easier and hold on to my only pressure tank!!

 

[Geoffrey Graydon]

Sorry to beat a dead horse but I’m having the same problem with 2 different motors.

I converted 2 7.5 motors... one a 1956 the other a 57.
one using the vacuum cap method.. the other filling the channel with hardener.

both motors start and run beautifully...

both motors when at high speed stall and need to be re primed with the fuel primer bulb to start.

they also both will stay running at high speed if I keep squeezing the bulb

ive used different tanks and lines to make sure it’s not the tank...

it’s like the fuel pump isn’t sucking fuel fast enough...

what am I doing wrong?

If you are taking the pulse from the manifold presumably you are connecting to the pump with a hose.Said hose needs to be as short as possible otherwise the pulse cannot generate and sustain sufficient vacuum to maintain flow.Fix: move the pump closer or use smaller bore tubing.