While riding this weekend, I found that while riding in a small creek just a few inches deep, my Scrambler could hardly get through it. If I got a good start on dry land, I could get the RPM's up and have some decent speed, but once I got in the water, all power was lost and I couldn't keep up with myself....It also didn't matter if I was in 4x4 or 2x4, it was bogged either way. Everywhere else it seemed fine, hills, sand, ect....any ideas??

btw, I have a 99 scrambler 400 4x4

Thanks

I used to notice the same thing. Whenever I rode thru a creek only 6 inches deep I noticed my Scrambler would lose power. It never completely died but I could tell it was running alot different while I was in the water. As soon as I would cross to the bank it would run fine.
I always thought I was just imagining it or something cause I could see no reason why the water would affect the way the engine ran. Only thing I could think of was the wires that run to the front hubs might be shorting out or something. My hub seals were bad at the time and since I replaced them I haven't noticed the problem again. Go figure.

My '99 Scrambler 500 does the same thing. While mudding it will begin to choke out about every ten seconds. Almost predictable. It loses a lot of power but will go again in a few seconds if I stay on the gas. If I let off it will die. One day I slowly backed in my lake with the water about 1" below the belt exhaust. I let it idle there for ten seconds. Put it in forward gear and it would bearly take off. It moved slowly then cleared up and took off like nothing happened. I'm a pretty good mechanic and can't pin point the problem. Sure would like to fix it.

The solution may be to seal the spark plug boot. Just take some di-electric grease (found in any auto parts store) and put it in the boot. This essentially waterproofs the spark plug. This should take care of any spark-related problems in water. If its not that, then i dont know what the problem is.

This is a common problem with many brands. The atv fuel system relies on gravity feed and carb venting. Those long hoses venting your carbs often suck water and can no longer vent, which causes bogging. Also; when crossing water; go slow. Flying through the water at high speeds only throws the water where it doesn't belong. Often; the water ends up in the clutch housing causing belt slippage. Check to make sure the seal behing primary clutch is not damaged as well. The older style clutch covers are known for warping as well. This causes water seapage. I have never had a problem with my 400 2x4 or 4x4 Scramblers in water. If you have altered the airbox or intake tube in any manner; look no further.
Good luck!

The spark plug thing makes sense, my cap seems really loose on the plug and falls off if it is really bumpy. But then again the airbox has been messed with, so I will check that too.

Thanks for the tips.

I rode my Scrambler in the lake today. I drove through water that come over the front fenders. It was lots of fun but it still bogs down at times. The belt can get wet if it bogs with the cover exhaust under water. I do have a simple mod on the exhaust to block splash and that worked real well. I'm going to grease the spark plug boot and maybe plug the fuel drain line when in deep water. I'll let you know how that works out.

I put dielectric grease on the spark plug and blocked the drain coming from the bottom of the carb. None of that helped at all. Gettin' PO'd.

Hmmm. When your quad goes through that water; when you get on the gas does it rev up but go nowhere? If it does this that means water got into your clutch housing. Usually just wait for about 5 min and it drains out. However, this happens when you go into deep water past your snorkel and not just splashing around. The snorkels are usually located near the gas tank. So splashed water shouldn't bother you too much.

I had the same problem on my 300 Xpress. It is only 2-wheel drive so it wasn't any wires with the 4-wheel drive unit. I could not narrow it down either. I ended up taking a garden hose and started sprayin the front of my quad down low as if it was water splashing up. I finally found my problem when the motor bogged down. I had a small crack in the CDI box. A little silacone and 6 months later I still haven't had any problems. The CDI box might not be your problem but the garden hose thing might help you troubleshoot. Hope it helps.