83 thunderbolt 50 botched lync and sync ran great just before it died!

Rugmanric

Recruit
Joined
Jun 17, 2012
Messages
2
So it started with a fuel pump rebuild due to surging, then I noticed even without a tach in the boat it was idling high and burning excessive gas. Timing and lync and sync right, after researching the method on the forum to get it close I figured for $9.00 I could get the full factory manual for the year and model I needed and get it perfect. Wrong, we mutt led our way through factory directions with a test tank, set the idle screws out, reseated the air needles at 1 1/2 out, the base timing set to just below 9 btdc,locked the screws on the primary plate, then adjusted maximum spark to 32 btdc, tightened the max spark to the stop plate..... Done with the motor on stuff. Then I thought while I'm in here why not get the idle down perfect, closer to 7 btdc, I adjusted the throttle stop out a turn, cranked it it ran for a couple of seconds then stumbled, died, and never recovered. No starting even with minor air inlet adjustments. Put it back, right. Throttle stop back to where it was, one turn, then nothing. Cranks over sputters no start. Now leaking gas from bottom bowl nut or seal? Also noticed no movement in choke plates at all, wide open all the time. Help please!
 
Joined
Jan 17, 2011
Messages
73
Re: 83 thunderbolt 50 botched lync and sync ran great just before it died!

Check spark and compression. Choke plates should be open unless your choking it......then they should be closed
 

Rugmanric

Recruit
Joined
Jun 17, 2012
Messages
2
Re: 83 thunderbolt 50 botched lync and sync ran great just before it died!

Will do, I've read a little more and decided to slow down and start again. I hope it didn't do any damage to the carbs since the lower one is leaking. I'm figuring it's just a problem that arose not related to the timing. Just to clarify the butterfly's stay open all the time, even when choking from the key on first start? Any clue if that's whats flooding the lower carb? The motor may not have been sitting perfect level but Only slightly tipped forward.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: 83 thunderbolt 50 botched lync and sync ran great just before it died!

Sounds flooded to me.Bottom carb needs servicing.Remove and strip down and clean with carb solution.Replace needle/seat.Check float still floats..Float must be reset to correct height.Rebuild with gasket kit.
 
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