2-stroke PWC Bogging down.

TownieRinker27 · 06-14-2021, 01:25 PM

Hi all,

2004 Yamaha Waverunner XLT1200. 3 cyl 2-stroke. New plugs, fresh mid-grade gas. Starts and runs fine. All 3 cylinders have ~100psi (almost no deviation) in a compression test. Headed out on the lake the other day. Ski took off - hit 45mph quickly. Within about 250 yards or so, motor bogged right down and sounded like it was running in mud. Top speed dropped to 35mph wide open. Tested sparks - all 3 plugs sparking. Not really that wet, but a bit. Black tips.

Specs attached.

So, is the mixture too rich? Seems odd that it runs well, then bogs down. Wouldn't the mixture be the same no matter what?

Clogged fuel lines? Seems like that would also be a constant problem.

Winterizer oils stuck in the carb?

I'm sure I will be chasing these, but I'm hoping to start down the right path first.

06-14-2021, 01:25 PM	#1
TownieRinker27 Junior Member Join Date: Jan 2017 Posts: 12 Thanks: 0 Thanked 2 Times in 2 Posts	2-stroke PWC Bogging down. Hi all, 2004 Yamaha Waverunner XLT1200. 3 cyl 2-stroke. New plugs, fresh mid-grade gas. Starts and runs fine. All 3 cylinders have ~100psi (almost no deviation) in a compression test. Headed out on the lake the other day. Ski took off - hit 45mph quickly. Within about 250 yards or so, motor bogged right down and sounded like it was running in mud. Top speed dropped to 35mph wide open. Tested sparks - all 3 plugs sparking. Not really that wet, but a bit. Black tips. Specs attached. So, is the mixture too rich? Seems odd that it runs well, then bogs down. Wouldn't the mixture be the same no matter what? Clogged fuel lines? Seems like that would also be a constant problem. Winterizer oils stuck in the carb? I'm sure I will be chasing these, but I'm hoping to start down the right path first. Attached Images