timing an outboard without a test wheel

[blgrams]

I have just finished rebuilding my 1991 40 hp johnson. I replaced the VRO with a new standard fuel pump. The motor runs pretty good except at idle. is there any adjustment I can play with to make it run better at idle without using the very expensive test wheel which I do not have. By the way, I forgot to mention I have rebuilt the carbs and set all carb and linkage settings up to the defaults listed in the clymer manual. float level, turns for needle valve for low speed, length of 2 linkages, position of adj arms in relationship to each other, carbs opening and closing the same amount at the same time, etc.

 

[Dhadley]

Re: timing an outboard without a test wheel

The test wheel is used for setting the timing at wide open. You may have to play with the carb settings slightly to "dial it in".

 

[Dhadley]

Re: timing an outboard without a test wheel

Make sure youre using the right Champion plugs and fresh 87 octane fuel.

 

[G DANE]

Re: timing an outboard without a test wheel

You can set the WOT timing at crancking speed, when both plugs are out of threads and grounded. Advance trottle to wot, let starter cranck motor and leave plugs sparking in the open air. Set wot timing to 4 deg less than specified, and the rpms will add the extra 4 degrees when motor is running.

 

[rodbolt]

Re: timing an outboard without a test wheel

it still needs to be verified at WOT. <br /> wheather you do it in the lake on a dyno or with a test wheel. it needs to be verified.<br /> good luck and keep posting

 

[blgrams]

Re: timing an outboard without a test wheel

thanks for the WOT advice. should I keep the two low speed skrews set to the same number of turns when I play with them?

 

[Dhadley]

Re: timing an outboard without a test wheel

The mixture screws may not end up exacly in the same place in each carb. The turns listed in the book are a starting point. From there its whatever makes the motor run the best. It shouldnt be too far off from your starting point.