Et250 bog

O

Old Iron

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Mar 10, 2013
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17
Age
54
Location
MN
I have and 80' 250 that I'm trying to sort out. I have switched it over to a 34mm Mik round slide And installed a UFO. I am running a 17.5 pilot and a 220 main. I can't seem to get rid of the bog off idle. Anyone else on here have any insight?

Thanks
 
I did the switch a year ago. Used a #30 pilot needle and a #220 main........ it runs just fine. Don't know much about the needles, but it might be worth looking into a different size pilot.
 
I should also note that I am running a
6FJ43 needle
159 P-8 valve
2.5 slide
 
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Hey Paulver, what are you using for an air filter?

Old Iron, I'm having similar problems and I'm running a similar set-up. Runs great once I get it past the bog, and it's hard to start sometimes, floods easily. I keep going smaller and smaller with the pilot which seems to make no change. I'm thinking either the air filter is too restrictive or the inlet valve is not correct for the fuel pump I have.

Matt
 
I have a "Pod Filter UP4229SA" from Dennis Kirk, Part #305783
$17.99. It band clamps right to the carb. I have the same sled.... 78 ET250. Runs like a champ. However..... there are four versions of that sled. 250A/250B/250C/250D. Not sure what the differences are, but I have the Service manual for them.
 
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matty k said:
Hey Paulver, what are you using for an air filter?

Old Iron, I'm having similar problems and I'm running a similar set-up. Runs great once I get it past the bog, and it's hard to start sometimes, floods easily. I keep going smaller and smaller with the pilot which seems to make no change. I'm thinking either the air filter is too restrictive or the inlet valve is not correct for the fuel pump I have.

Matt
Click to expand...
I hear yah. It runs like a scalded cat once you get past 1/8 throttle. I tried a #25 pilot today that seemed to work a little better but still far from perfect. My plug is a nice coffee color as well. The little beast did 60mph with my 175 pound son on it. IDK what else to try. I think these yammie 250's just run this way.
 
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Paulver said:
I have a "Pod Filter UP4229SA" from Dennis Kirk, Part #305783
$17.99. It band clamps right to the carb. I have the same sled.... 78 ET250. Runs like a champ. However..... there are four versions of that sled. 250A/250B/250C/250D. Not sure what the differences are, but I have the Service manual for them.
Click to expand...

Thanks Paulver for supplying the part number! This is interesting...I bought the filter from Royal Distributing here in Canada. Old Iron, check out this thread from DooTalk:
http://www.dootalk.com/forums/topic...-royal-distributing-are-they-the-4245-s-ones/

If you read down, they're claiming the filters sold at Royal aren't the S version for snowmobile use...Which is where i bought my filter and must be what I have. The non S version is much more restrictive than the S version. Which would explain why I'm running rich on the bottom end. Not sure if it helps you at all but it sure seems to explain a lot for me.

Paulver, the A/B/C/D versions refer to the model year, A='77, B='78, and so on.
 
I've been working at getting the jetting right on the kids' ET250B as well. 34 Mikuni on it, I forget where the jets are by now, I'll write it down next time i havethe carb off. Got it to where it runs fine below -20c, but when it warms up and the kids are riding it loads up with fuel. If I'm riding it I use a lot more throttle so it doesn't do it as much. Guess I'll have to try going down one main jet size. I know i need to up my pilot one, as I'm turned right in on the air screw to get a decent idle. That's interesting about the Royal filter pods, I have the green one on mine as well, not the black snow one. One thing i have found is to get decent takeoff the idle needs to be higher than what I would normally set a sled at.
 
Ok today some progress! Took the Uni Filter off and ran with an EMGO motorcycle type pod filter I had in the parts bin. MUCH better! It's still a little boggy off the bottom but it's a major improvement and it's certainly driveable now. I don't have to pump the throttle just to get the sled to move. It also has a consistent idle now, it used to idle high then drop down low after a period of time, presumably once the carb loaded up with fuel. Here's my settings:
220 main
30 pilot
6DH4 needle (2nd clip from bottom)
159 0-0 needle jet
EMGO air filter
 
Paulver said:
I have a "Pod Filter UP4229SA" from Dennis Kirk, Part #305783
$17.99. It band clamps right to the carb. I have the same sled.... 78 ET250. Runs like a champ. However..... there are four versions of that sled. 250A/250B/250C/250D. Not sure what the differences are, but I have the Service manual for them.
Click to expand...

i have the exact sled and I'm in the middle of a restore?rebuild and need a service manual. (1978 enticer 250) can you help me with a manual if you have a downloadable one.

thanks.
 
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