jlo440 seems to not want to run

[chris lewis]

hello all,
i did a quick compression test and both cylinders read 135 which i have to thk is very good. my vw bus engine has less than that and it runs...dangit!

the engine is sitting on a mount that tilts it towards the rear of the machine. i think the engine is a 440-7. i have two standard intake manifolds for single carbs. i am going to get the mikuni carbs offered to me and will try those. they came from a running engine and they come with the manifolds and cables.
they come off of a attex.

thanks for all of the input....

chris

[Bazooo guy]

Before you replace the carb you should determine if thats the problem.
Is the engine not getting fuel or getting too much.
If you spray gas/oil mix into the carb will it fire?
When you spray it hold the throttle wide open so the fuel gets past the throttle plate.

Sometimes the crankcase has a drain plug that could be missing or an open fitting or is just leaking somewhere.
If the case has a leak it will not run properly and spit gas out the carb and exhaust and backfire in both directions.
2 strokes will foul plugs quick if not tuned properly and spraying fuel into it doesnt help.
If you pull the sparkplugs and they are wet its flooded. If they are dry its probably not getting fuel.

[chris lewis]

hi all,

i checked for vac leaks etc a nd found nothing to report. i did find that i mistakenly identified my carb as a wda 52... it is a wda4. i really do not know wht the difference is specificationwise. when i got the machine the carb on it was the wda 52... but the engine i purchased (400) had that wda 52 on it. i used that carb since it seemed more complete and i rebuilt that one. the wda
4 seems to be missing the high speed needle.

i did get it running by squirting some gas into the carb throat...but again, it just seems to run up in rom, then die. if i keep it choked it seems to run a little bit longer but not much...leading to the ida of an air leak...
i pulled the carb off and tore down the wda4 to compare it to the wda52....that is as far as i got.

chris

[Bazooo guy]

Wda-4 is for the Jlo 440cc

Wda-30 is for the jlo 400Cc and 440cc

Wda-52 is for a kohler 440cc

Is your impulse tube external or part of the flange on the intake side?
Is the return line connected to the tank above the feed line?

[chris lewis]

great...thanks... do youknow if there is supposed to be a needle for high speed on the wda4 carrb? Mine has a screw where that needle would "normally"be. on the wda 52 there is a high speed needle and it inserts into a brass tube as you look into the venturi of the carb. my wda4does not have that part.

the impulse tube runs from the bottom of the crankcase up to a nipple on the carb diaphragm stack. it does pump...as there is gas getting pumped into the filter bowl ...a plastic filter that is screwed onto the carb inlet side...and therre is gas...and bubbles...pumping out of the carb into the return line going back to the fuel tank.

are there any good shots or parts breakdowns for the diffent carbs? i have a generic walbro manual that has a generic walbro parts diagram.

can i use the 52 carb? what is the difference between the kohler and the jlo that dictates the use of different carbs?

thanks again.

chris

[Bazooo guy]

*
Are you sure its not a WY or WZ series carb....they have a screw and large washer instead of *the needle on top
Does the screw turn when the throttle is opened.

The wda52 is a bigger carb. *The size of the carb is based on how the engine breathes...from the intake to the exhaust and everything in between.
A wda52 probably has a different size jet on the 400cc than it would on the 440cc
You can try it to see if it starts but tuning it might be difficult.

Heres some info

http://www.vintagesleds.com/library/manuals/misc/walboro/Walbro-WD-WDA-WR.pdf

[chris lewis]

The carbs are stamped:
WDA 52
WDA 4

The WDA4 was on the engine I bought that supposedly ran. This is the carb that I rebuilt and currently have on the JLO 440 in the Max.
The WDA52 was on the engine that was in the 6 wheeler when I bought it. At that time, the engine was locked up as the PO ran it without a fanbelt and burned up the piston. .

My WDA 52 is missing the power needle and has a screw where the needle would have been.

Thanks for the link! That is great.

Chris

[demo61x]

The JLO 440 that was stock in my 1970 articat panther snowmobile ran the same way after its rebuild. I tried everything with no luck. turned out the mag and pto seals on the crankshaft were dry and bad sucking air. you can check this out by sealing off the intake and exaust ports of the engine and hooking a hand vacume pump to the block port where you get pulse vacume for your fuel pump. should hold vacume. I believe it is about 9 inch pounds. hope this helps you out, let me know. Rob

[Bazooo guy]

Look at page 1 of the first manual i posted.
Is that the screw on top you are talking about?
If yes its not missing the needle. The screw should turn with the throttle.
Pg 23 describes how it works

[chris lewis]

MOderate success. Hi all, I have been moderately successful in getting the engine running. I cranked the idle jet screw out and close the choke a bit. So, it seems that it is starving. I was able to have a decent idle ...not racing as before. I think that it was starving for fuel.

I was using the electric start until the battery died and then went to pull start. I think I broke my finger pull starting it. Dangit!

Anyway, I was getting closer to having it run. I placed a clamp on the impulse line where it mounts to the carb...just to eliminate any air leakage. Also pulled the carb completely apart and adjusted the float needle arm..not sure if that helped.

I stopped as I was smoking myself out of hte garage...hope to mess with it this weekend.

I did buy a set of mikunis from a gentleman off of his JLO 440. These were on an ATTEX...so new question: on my MAX, the engine sits rocked backwards. The attex apparently sat more upright...is that a problem for the carbs?

Thanks
Chris

[hydromike]

Hey Chris,

On the Attex, the JLO sat "perfectly" upright. This likely will be an issue with your carbs, since the float bowls on the Mikunis need to sit level. You have a couple options, neither of which are really all THAT easy to persue.

*you can build a new engine mount to level the engine out, which may require substantial changes to exhaust, drive belt etc.
*you can either find (if they exist) or build flanges that will keep the engine at its angle and level the carbs out.

Regardless, the carbs need to be level.

[chris lewis]

Ugh...OK...Anyone need a set of Mikunis with intakes from an ATTEX JLO 440?

I will be getting them in the next few days and will evaluate the situation...altering the engine mount will run the exhaust manifold into the belt unless I raise the engine up...which then will end up hitting the body.

Sounds like I made another blunder...unless I can turn it around. I think the option here is to modify the manifolds. We will see if they are aluminum or steel.

Question for you carb gurus: are the jets different between a WDA4 and a WDA 52.

When I pulled the WDA4 apart, the Idle circuit did not have a jet in it...the jet seemed to be a part of the housing. Additionally, it did not appear that there was a jet on the HS side...wheras the WDA52 had a brass jet in both places.

Thanks
Chris

[Bazooo guy]

Can you post a pic of the carb you are working with?

[chris lewis]

OK, I finally had time to load some picture of the carbs. I am not sure how to link to the pictures but they are in the ENGINE category in the gallery. I just loaded them so they should be some of hte latest loaded pictures. I am going to try to link to a picture...hopefully that will workJLO 440 in Max carburetors - Amphibious ATV Pictures If this link works, there should be a number of pictures of the carbs.

Really quick..I was able to get it running this AM...but I have to run with the choke closed slightly...and then it runs at high RPMs as I ran the HS needle and idle needle out...I did notice that when I squirt fuel oil mixture in the carb that, if sprayed at the throttle shaft, fuel will spritz out of the shaft area. I grabbved the shaft and wiggled it...it is not super loose but could this be some of the problem with the engine not running? It is not crazy noodled out.

Thanks Bazoo guy and all for your help...I am just really frustrated with this darn thing!

[demo61x]

check the damn crank seals !!!!!!