2004 MXZ 800 HO needs choke to run

[Highmaintenence]

I have a 04 MXZ with the 800 HO...sometimes I have to leave the choke half on to keep it running when I ride...not warming up. I've cleaned the carbs and the reed boots appear to look good. Anyone seen this issue before. I know a few of the Doo's have had issues with boots.

Cheers, J

 

[maxwell]

test your dpm system

if its equiped..

 

[Highmaintenence]

Hey Maxwell,

Thanks for the reply How do you check the DPM? Dealer?

Cheers, John

 

[imdoo'n]

i'd say you have gummed up jets. did you take them apart and soak carbs in carb cleaner, was there any greenish mung in bowls or jets. did this start to happen after a long storage like over summer? you may also have a plugged fuel filter in tank. not very likely to be dpm related, more info would be best.

 

[maxwell]

i'd say you have gummed up jets. did you take them apart and soak carbs in carb cleaner, was there any greenish mung in bowls or jets. did this start to happen after a long storage like over summer? you may also have a plugged fuel filter in tank. not very likely to be dpm related, more info would be best.

tell me how it isnt dpm related. had many of sleds through the shop with similar issues. dpm solenoid was always the culprit.

if its happening below half throttle the main jet wouldnt even come into play. but check the mains and pilots. pilots are more likely to gum up and clog

may not be it. just an idea.

to test simply unplug the dpm manifold and hook it to a 9v battery and you should hear a clicking/buzzing sound

 

[CUSO]

What temperature/elevation are you running? if it is happening also at low elevation, it most likely isn't your dpm. Pull a hose off the DPM manifold and see if it changes.
Drain out your tank/bowls and try some fresh fuel. To use your choke, you are richening up your fuel mixture

What do your plugs look like?

 

[sheebansavage]

Just a shot in the dark, but have you adjusted your idle screws?

 

[maxwell]

Just a shot in the dark, but have you adjusted your idle screws?

do you mean the idle speed screw or the mixture screw?

idle speed screw wouldnt effect it there is one that sycs between the 2 carbs so it cant be missadjusted

 

[Highmaintenence]

Did clean the carbs. Clean fuel ....It's actually my buddie's sled. He says his clutch is set at #4 when he was in Renshaw. Thanks for all the info guys! Much apprecaited.

 

[TheLonelyIsland]

check your fuel filter , i have had this happen to before and it solved it!


good luck!:d

 

[Highmaintenence]

Plugs look good, have adjusted the idle screw. I'm kinda wondering if the clutch needs adjustment. My 09 Summit max power is 8200, the 04 HO is 7900...what do think??

 

[Modman]

Plugs look good, have adjusted the idle screw. I'm kinda wondering if the clutch needs adjustment. My 09 Summit max power is 8200, the 04 HO is 7900...what do think??

How are the clutch and choke related? I don't think adjusting the clutch finish RPM will help with needing the choke to run. Idle screw won't do jack, need to adjust air screw instead.

If the fuel filter is plugged and will not flow enough fuel into the carbs with the choke off, how is it going to flow enough with the choke on? Fuel supply flow is still the same to the carbs with the choke on or off.....??? choke circuit fuel comes from the same fuel line as the float bowl fuel from the tank....

I would try adjusting the air screws first (not the idle screw!), then bigger pilots and clean carbs and blow out all carb passages, double check all lines on the DPM and vacuum, if this doesn't work then I would look at the DPM and test the solenoid.

Does this sled have any modifications?

 

[DRD]

DPM fails full rich, running with the choke should make it worse no?
One step at a time, don't do anything until you are 100% sure the carbs and all the circuits are clean and working.

 

[Highmaintenence]

Wow, I gotta admint I rely on guys like yourself to help me along with my sled repairs and so on...will pass your notes on to my buddy. No mods and thanks for the info.

 

[maxwell]

DPM fails full rich, running with the choke should make it worse no?
One step at a time, don't do anything until you are 100% sure the carbs and all the circuits are clean and working.

weve discussed this before and that is how its designed but not always reality.

the dpm may not have "failed" but could be stuck or sticking who knows.

i beleive 7900 is the rated rpm for the early series III engines but cant remember.

 

[Deano670]

Is it hard starting?? Cold or warm doesnt matter.

 

[kellyandhislimo]

DPM fails full rich, running with the choke should make it worse no?
One step at a time, don't do anything until you are 100% sure the carbs and all the circuits are clean and working.

ya what he said, something tells me this guy know alot about "mechanics":d

 

[mxz sledhead]

check the fuel pump my 800 just did it this winter pick up some bad fuel and it plug up the diaphragm it was a real bi... keep it going specially in mc bride trip new pump its back being wildthing now

 

[DRD]

weve discussed this before and that is how its designed but not always reality.

the dpm may not have "failed" but could be stuck or sticking who knows.

i beleive 7900 is the rated rpm for the early series III engines but cant remember.

Sorry, I didn't realize the DPM had been gone over is such detail.

If it's stuck "open" and trying to lean the motor out so much it needs the choke to idle, the first WOT run would have you coming home on a strap.

Simple test, unplug the vacuum line (source) and plug it. Leave the lines going to the bowls open and it should run like any other non-DPM sled.

 

[maxwell]

Sorry, I didn't realize the DPM had been gone over is such detail.

If it's stuck "open" and trying to lean the motor out so much it needs the choke to idle, the first WOT run would have you coming home on a strap.

Simple test, unplug the vacuum line (source) and plug it. Leave the lines going to the bowls open and it should run like any other non-DPM sled.

A non dpm machine runs s way larger main jet something likme 10 to 13 sizes. So it would run like crap above half throttle I would think. Someone correct me if I'm wrong tis what I have discovered with a non dpm machine I had at the shop last year