No low speed power

[99xplimited2]

Just got a 99 xp limited, it has after market air filters and maybe more modified that I haven't found yet.

Starts fine, when you fully press the throttle it really doesn't do anything, then about 4 seconds later it slowly builds speed. It tops out at about 35-40(speedo not working) at about 4800 rpm. Once riding two up it took over 15 seconds after throttle pressed down fully(It doesn't go over idle speed or change engine sound at all until it finally starts accelerating)

I checked the fuel filter, clean. I pulled the plugs they were dark and wet, as I figured they would be(it smokes a bit and smells of gas from a tube behind the pwc) I will get new plugs after work.

I haven't checked to see what jets are installed or where the needles are set. I took the top off the raves but didn't pull anything below the spring. This is our first pwc and I don't really know what to check next.

 

[Bills86e]

You can check your pop-off on the ski! Other things would include rectifier, raves,
and water regulator function, exhaust leaks, fuel routeing.

 

[99xplimited2]

I've done extensive searching since it was bought. Nothing that I can find matches my problems.(I probably have more than one)

I am aware of the fuel line problems, and I will do it someday, but since the fuel filter looks clean as a whistle, I will not worry about it until winter.

Brand new gas and oil, I haven't tested the compression yet.


I replaced both plugs today, I had previously only removed the front one(it was black and wet) today when I replaced the rear one it was dry and light grey. So it seams the front is rich and the rear is lean. I guess I will tune the carbs next, at least get them to factory settings then I can go from there.

Otherwise its going to the shop after I test it in the water later this week.

 

[daverade]

hope this helps get up to speed

(it smokes a bit and smells of gas from a tube behind the pwc).

dude the "smokin tube" is the exhaust...this is normal...LMFAO.....your carb's have internal filters in them...so just because the one up front is "clean as a whistle" does'nt mean the gas lines/veins/and filters are actually clear...this could be causing your plug indifference homie....and someday? if you got the ski in your posession, I would most def make this a priority, and the "tempo" lines... i would make it top priority....bet your problem disipates!!!! good luck, keep postin'

 

[99xplimited2]

dude the "smokin tube" is the exhaust

Yes I'm aware that it is the exhaust!

Smoke is a big part of tuning in nitro remote control cars, so I include all the information I possibly could.

 

[99xplimited2]

Okay I now have good low end power I replaced the fuel lines and clean the internal carb filters, but it won't top out. I can hit 4750 rpm and thats it, and about 35 - 40 mph.

I Cleaned the raves off, there wasn't much on them.

I checked comp. seems a tad lower than I thought it should be mag = 100 pto = 110.

The high speed needles are set at 3/4 out

I checked the spark plugs(not new plugs same as the last test) afterward mag cyl. was black pretty much everywhere. pto was shiny metal, no black and a little moist it smelled more like oil than anything.

I'm going to check the pop off pressure next, I'm running out of ideas.

 

[gsxgtxman]

Looks like a new top end in your future! The compression readings are to low! Ideally you want to see 130-150 +\- 10! Around 100 is when it's time for a top end rebuild!

Did u do the test on a cold or warm engine? Did you ground the boots to the black box?

 

[99xplimited2]

Did u do the test on a cold or warm engine? Did you ground the boots to the black box?

The engine was cold, I did not ground the boots. Will that make a difference?

 

[Bills86e]

Clean plugs tells us fuel is washing them.

 

[99xplimited2]

I took the head off, the pistons are stamped 25, the walls don't look scored to me. There seems to be something above the surface of the cyl walls, like rust but not on the bottom or top just the front and back(sides) of both cylinders.

I'll measure the cylinders later to make sure they are just 25 over.

What are peoples thoughts on just rings or pistons and rings without a bore out or re sleeve, I would hone it though. Does anyone ever do that? Or do the cylinders get out of round, then that wouldn't work.

I haven't gotten the cylinders off of the bottom end, seems kind of stuck. So i'll check the crank rods and the rest of the pistons later.

Both pistons and the dome of the head matched earlier reports of the spark plug condition. Mag was really black, pto head was clean piston was black in the center.