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Help! Wife’s coming for me Sea-Doo!

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This concerned me, it's normal?

"Anyway- put her on the water and got more bogging mid range - expected from residual premix- but smoother acceleration- a little bit of a bump to wide open throttle but much better than before. "

Yes, the mid range tends to be a little rough on the 787. Not as noticable accelerating from idle to WOT, but hanging around in the mid range.

It should't be bogging though, that's carb or fuel delivery issues.
 
I have a crappy gasket on the MAG carb- have thicker ones coming in the mail today so I’ll slap one of the oem ones on..

Everything’s trying to tell me SOMETHING. What is it???

In a pinch, I make gaskets from single ply department store shirt box cardboard, especially for testing purposes or if I'm anticipating being rough on them.

We're dancing on the head of a pin when we're at the point of final tune, it's better to be conservatively rich with hint's of 4-stroking than lean (hesitation). It's not clear whch of these you're experiencing, perhaps bogging means slightly rich?

Easy warm restarts are part of a low speed mixture screw adjustment goal. We're shooting for a happy balance of crankcase fuel at low speed where idle RPM aren't trending down and need a throttle blip to clear out excess fuel collecting in the crankcase.

If there's too much fuel, plug fouling becomes the issue. If there's not enough fuel, detonation occurs (detonation becomes an issue at speed where heat is produced, not an issue while idling and putting around). Detonation will torch pistons with heat and the clue presents itself as hesitation.
 
Yes, the mid range tends to be a little rough on the 787. Not as noticable accelerating from idle to WOT, but hanging around in the mid range.

It should't be bogging though, that's carb or fuel delivery issues.

Right, my focus is on the description of bogging. If he means slightly rich this is much better than lean hesitation and might be acceptable.

ie: as fat as possible without appreciably impacting performance or prematurely fouling plugs.
 
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It concerned me a little too; I don’t think it’s of much note but I’ve been running with just the flame arrestor on and not the airbox- maybe that will help a little with the PTO carb but it’s probably going to make things worse for the MAG.


Both mag and PTO should have the same color assuming both have equal time on them. Installing the factory breather richens things up, ie: without the breather a lean condition (with perhaps hesitation, even) can be anticipated.

If you have one cylinder loading up on fuel (black fuel soot is an indicator, brown is a normal color of decomposed oil), it's time to confirm a reasonable pop (which can be accomplished without removing the carburetors).
 
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Yes, the mid range tends to be a little rough on the 787. Not as noticable accelerating from idle to WOT, but hanging around in the mid range.

It should't be bogging though, that's carb or fuel delivery issues.

That's my understanding, the 787 was tuned slightly fat part throttle. It's important to differentiate lean vs comfortably fat though.

Another aspect that seems encouraging in this case is there's no mention of the engine falling on it's face and quitting like it ran out of fuel (too lean).
 
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Did you ever do a compression test? Seems like you really need to start there since you have a big difference between cylinder plug readings.
 
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