Need some service assist on 1958 FD-12

[DrummermanBob]

I have taken an FD-12 as far as I can and have an issue with idle coughing. This old beauty has all new electronics, re-built carb, fuel lines and filter,  lower unit impeller and all seals, upper and lower crank shaft seals, fuel pump conversion. I just don’t have the expertise to diagnose what is going on.

Is there anyone in the Twin Cities that can be recommended to take a look at this?

[crosbyman]

what fuel pump did you use for the conversion … apparently  the round  ones with the brass mesh screen    have had some issues.

try  openning up the LS screw needle a bit a time

 

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[DrummermanBob]

I have played with needle adjustments to no avail. It’s a Sierra pump (consensus recommendation from AOMCI members responding to an earlier post from me.

[crosbyman]

what model …???       round……. square like Mikuni …..

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[DrummermanBob]

18-7353

[crosbyman]

well that should work fine.

 

are you using the  old air nipple  as a pulse line  source with one  channel sealed off  ?  or did you  tap a cover and   plug the nipple  method ?

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[seakaye12]

I would try adjusting the link-n-synch in both directions to see if you can tune out the cough.  The settings discussed in the manual where you line up the mark on the cam with the roller are really just guidelines.  At meets I have seen where adjusting the link-n-synch on motors like yours can make a big difference.

[labrador-guy]

Drummerman I gotta get my two cents in here.  Coughing/sneezing are caused by lean mixtures.  Recheck the fuel lines from one end to the other.  Check the fuel filter glass bowl and it’s gasket.  Make sure your fuel pump is assembled correctly.   It must be sucking air someplace.  Plug off the old pressure fitting on the read plate.   Did you blow with compressed air the low speed jet drilling?   I mean take the low speed jet out and make sure there is no gunk stuck under the soft plug.   I have two of those old timers and they run just great.

dale

[crosbyman]

see manual page on carb adjustments …see  NOTE … on sneezing

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[reivertom]

Are you using the big box store grey fuel lines from the tank? They have a history of the inside liner collapsing and choking off fuel to the carb.

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