Running 7 mph slower than before linc&sync

[rfields109]

72 50 HP Johnson

Timed at 3 deg at no load idle, with load about 4 deg at 750 rpms and 19 degree's at WOT

Appears to have a loss of spunk on take off and instead or seeing 32mph I'm barely able to get 25...

Could one of the carbs be not opening all the way, woul dthat cause something like this? OR did I set the low idle timing incorrectly ? And would that cause a similar loss of power? Did I move the power band?

Runs smooth but surges at WOT under load on the water.

Almost have it righteous but boy have I learned a lot about Boat motor mechanics

Suggestions on what this might be?

Boat has 1 new coil pack, one old coil pack. Replaced a cracked one.

 

[Dhadley]

Re: Running 7 mph slower than before linc&sync

How did you set the wot timing? Did you move it from where it was before?

If the linkage going all the way (timer base to the stop & all carbs opening)?

Are you down on rpm or just speed?

 

[rfields109]

Re: Running 7 mph slower than before linc&sync

Down on RPM, but will surge and pulse moderately at WOT.

Timer base seems to move and adjust fine, we saw it at 22 degrees BTDC until we adjusted it. So yes we moved it and Now at WOT it is right on top on 20, closer to 19. running much better than before at idle up to about 20 mph ... And no we did not have a tachometer and had to guess at the rpm's... probably where we messed up.

Also prior to getting some crud in the HS jet on the bottom carb it would run great and jump up on plane and hit 32 at WOT.... just wouldn't idle for beans.

We used the service manual to do the link and sync but I am wondering IF one of the carbs is out of position with the other at WOT.