99 Outback LS stumbling issue

[SkiBoy]

My Outback is still not running right. Carb has been rebuilt, fuel pump checked and pumping plenty of fuel, fuel water separator changed, new plugs, checked compression, new cap and rotor, timing is advancing, still running poorly.

The boat idles perfectly. Revs up to 4 grand with no issue. Transmission and prop and shaft all checked. I put it in gear and as soon as I add throttle it stumbles and vibrates. Advance timing, no change, retard timing no change. 2 mechanics have looked at it and listened in the water. One doesn't know, the other thinks it could still be in the carb. I am stumped and frustrated. Only 200 hours since the engine was rebuilt.

[Stazi]

Either the timing isn’t advancing properly under load or the main jet(s) on the carb are not right.


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[parrothd]

Either the timing isn’t advancing properly under load or the main jet(s) on the carb are not right.


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Did you check the accelerator pump? Can you slowly get over 4000rpm?

[SkiBoy]

The timing is advancing. It will rev up to 5000 plus, just not under load. Carb was rebuilt, it idles better and runs smoother until you put it in gear.

All parts on the carb were replaced.

[parrothd]

The timing is advancing. It will rev up to 5000 plus, just not under load. Carb was rebuilt, it idles better and runs smoother until you put it in gear.

All parts on the carb were replaced.

Pour some fuel in the carb while it's stumbling.

[SkiBoy]

Will do that tomorrow. I have the carb off checking it over. Thanks

[parrothd]

Is the choke opening after starting?

[Stazi]

Hmm. Accelerator pump usually has a couple of settings you can select, try using the next one up that has a higher leverage and pumps more. But first see if you can sloooowly get up to 5000rpm under load. If yes then try the accelerator pump adjustment. If that still doesn’t help then the main jests may have been redone incorrectly or are not clean.


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[jtucker]

The carb rebuild kit I ordered came with the wrong power valve. So I had to buy the right one separately. Do you know if the correct one was installed during your rebuild? The wrong one could be causing your problems.

[SkiBoy]

Yes, I did get the correct power valve after calling Holley. Ordered it separately from the rebuild kit. I can't get past 1500 rpm without shaking and vibrations. I poured gas in the primaries and secondaries (just a little) and it wanted to stall. I retarded the timing it got worse...advanced....no change. Don't know if the choke is opening, it has always run rough at the start then runs better after it gets to 120 degrees or so.