2001 XLT 1200 rebuilt - issues after 1st hour of running - bogging down, misfires

[Teejay22]

Just had the engine rebuilt and put back in the ski. (Premix, d-plate, already had SBT improved PV so it didn't need the waveater clips, carbs rebuilt, new reeds,etc). I had purchased a D-Plate and waveater clips (ended up not needing either so I'm going to need to sell those).

Ran it for the first time in the water on Saturday...started right up and ran pretty well for the first hour or so of break in. There was a little bogging down or misfire around 2-4k RPMS, but it would go past it and then run well. It did seem to misfire (muffled pops in the exhaust) when accelerating, though overall I was impressed with the performance.

When I went back out to run it some more, it seemed much worse (lots of misfires, loss of power). It started smoking a lot more than it did when I was initially running it.

I was running a 32:1 mix for this first full tank, so I'm wondering if it was too rich and if that caused some problems. The rear cylinder plug (#3?) was wet every time we pulled it out after running. For the most part, plugs 1 and 2 were dark, but dry. Since it wasn't running well, I ran it to the boat ramp to get it taken out and on that ride it wouldn't go more than 5k RPMs, was smoking a decent amount, and couldn't get going more than 12MPH. If I pulled the throttle fully, it would bog down to the point of dying. I'd have to feather it to get it up to the 5k rpm.

Out of the water it revs fine and I don't hear the misfire/bogging down.

Looking for suggestions on a plan of action to tackle the issue.

Fairly new to the world of jetskis and have a buddy who has been doing most of the work on the ski for me (after sending the engine off for rebuild).

Thanks in advance for any suggestions!

[LETHAL RX7]

Who rebuilt carbs?

[87r]

bad coil, bad wire, bad plug or bad carb on that cylinder. Since its a new motor check compression across the board and make sure they are even and you didnt get a dud motor. If ok, Start with a new set of plugs and If possible on these (havnt pulled coild on these yet) swap the coils between 2 and 3 and see if the middle cylinder starts fouling. If so, your coil or wire is dead. If not, i would look into the carbs. the #3 carb may be leaky or someone miss counted their turns out on a needle

[Teejay22]

Just had the engine rebuilt and put back in the ski. (Premix, d-plate, already had SBT improved PV so it didn't need the waveater clips, carbs rebuilt, new reeds,etc). I had purchased a D-Plate and waveater clips (ended up not needing either so I'm going to need to sell those).

Ran it for the first time in the water on Saturday...started right up and ran pretty well for the first hour or so of break in. There was a little bogging down or misfire around 2-4k RPMS, but it would go past it and then run well. It did seem to misfire (muffled pops in the exhaust) when accelerating, though overall I was impressed with the performance.

When I went back out to run it some more, it seemed much worse (lots of misfires, loss of power). It started smoking a lot more than it did when I was initially running it.

I was running a 32:1 mix for this first full tank, so I'm wondering if it was too rich and if that caused some problems. The rear cylinder plug (#3?) was wet every time we pulled it out after running. For the most part, plugs 1 and 2 were dark, but dry. Since it wasn't running well, I ran it to the boat ramp to get it taken out and on that ride it wouldn't go more than 5k RPMs, was smoking a decent amount, and couldn't get going more than 12MPH. If I pulled the throttle fully, it would bog down to the point of dying. I'd have to feather it to get it up to the 5k rpm.

Out of the water it revs fine and I don't hear the misfire/bogging down.

Looking for suggestions on a plan of action to tackle the issue.

Fairly new to the world of jetskis and have a buddy who has been doing most of the work on the ski for me (after sending the engine off for rebuild).

Thanks in advance for any suggestions!

Why did you replace the original motor? What caused it to fail? Did you repair what caused the previous failure?

I bought it with the blown motor from the oil lines coming off of cylinders 2 and 3. Converted to premix. I sent it off to PWCengine.com and had Mike rebuild it.

[Teejay22]

Compression numbers below. Also attaching a video of the spark of each cylinder (slow motion). #3 seems a little slow and off of when it should be firing.

[Teejay22]

Should I attempt to pull the plug wires and test them with an ohm meter?

[Teejay22]

So the carbs weren't ever rebuilt?

Yes they were rebuilt with mikuni kits. I found out that he didn't drill holes to adjust the pins...does that need to be done? I guess they thought if they were leaving stock they didn't need to do that.

[Prism]

Did you remove the old fuel or run it through? I would also check this as well... http://www.greenhulk.net/forums/showthread.php?t=39216

[dockwalker]

Search here for O'sideBill's posts and check the carb settings.Don't blow the new engine without making sure the carbs are right.

[Teejay22]

Search here for O'sideBill's posts and check the carb settings.Don't blow the new engine without making sure the carbs are right.

We'll go through the carbs again.

Is this the info you are referring to?
http://www.greenhulk.net/forums/showthread.php?t=70129 This doesn't look like it is for stock setup though?

Or this one: http://www.greenhulk.net/forums/showthread.php?t=62751