Vaccum

[sparkroost]

I know I have asked this before, but I am gonna try again.<br /><br />Can I drill two holes in the manifold near the carburator for vaccum gauges to tune the motor(idle and off idle is the main concern)? Am I missing something here? I know there is vaccum there.. so.. seems only logical I can link-n-synk this way or compensate for worn linkage/shaft bushings.<br /><br />I was gonna do it anyway.. but I thought I would ask.. who knows.. I might be way of on this one.<br /><br />Also.. does anyone have a procedure for checking the proper jetting in the low and high range? Do I run the motor WOT and cut the engine and look at plugs/piston top? And for the low end, just idle for a period and check plugs/piston top?

 

[clanton]

Re: Vaccum

You would need a gauge with a dampner to steady the gauge needle.

 

[FlyBoyMark]

Re: Vaccum

Certainly....BUT most outboards have multiple carb engine unless the one you have is a single carb...you would need some sort of little manifold valve setup to shut off and turn on each carb to get the correct manifold pressure for each cylinder. JUS' MAKE SURE THEY DON'T LEAK AIR AND MAKE THE ENGINE RUN LEAN!!!!<br />And make sure the hole is between the reeds and carb and not the reeds and crank

 

[sparkroost]

Re: Vaccum

FLy, 4 holes. 4 gauges(I tune bikes with mercury tubes). Just have to drill the holes in the intake manifold near the base of the carb. No way to get it perfect cause there is no independant linkage adjustments to synk all 4. Basically have to just synk bottom 2 to top 2. Could get away with only 2 holes. 4 holes would allow you to see how far off or how close in relationship to one another they are.<br /> I would take the old linkage rod and plastic holders and toss them in the trash. Get some ball cups, studs and turnbuckles and replace linkage. Then all you have to do is twist the turnbuckle to adjust. On the turnbuckle there is 1 reverse thread and 1 forward thread. Turning the turnbuckle will get vaccum settings even. This should then make for better acceleration, fuel economy in the low/mid range. Link and synk will have little effect on WOT unless the plates are way off.