carb rebuild

[JONSSTIHL]

I'm have the carb off my 025 found out it is a walbro wt-215 with a k1 stamped in it

I was wondering about a little how to help on a carb rebuild. I rebuilt the tillotson on my little jonsered from the 70's but I didn't bother changing out the welch plugs since the inlet screen was clean

but on this carb, the fuel line is cracked and the fuel filter is XXX number of years old so I think I will opt for a complete rebuild without cutting any corners

what is a good way of getting welch plugs out, drill and pry or will they pop out with a little prying. and are there any specs for putting them back in

thanks for any tips

 

[Lakeside53]

Sharpen a small screwdriver or 1/8 steel rod flat like a chisel, then tap it it into the plug at about 30 dedress to the horizontal - justa tiny amount, or you'll bust into the carb body. Then just pop out the plug.


To re-insert new plugs, just place them in the hole and tap slighty on top with a flat punch to distort. No sealer.


I wouldn't bother.. just clean it out (no blasting of air) with a limited amount of carb cleaner, then soak it in straight gas for an hour or two.

 

[JONSSTIHL]

just the guy I wanted to hear from, so you think I shouldn't bother with the welch plugs. I haven't taken the carb apart yet but I did get the fuel line out, there are only two cracks and I don't think they are all the way through. If I can find my mityvac I will vacuum test the fuel line.

how do you get the intake manifold off, can't see any screws holding it in but it seems to be on pretty tight. I want to clean out the intake boot because a little bit of saw dust got into it but I need to take the white plastic manifold off first. the service manual doesn't mention it specifically except it looks like I need to take the engine out of the case to take it off.

have you ever seen a fuel filter like mine, I will post pics later but I almost feel like keeping it, it looks clean, the filter is held together with a screw and looks kind of like the stihl 350-3500 but the insert is some kind of porous metal. looks kind of like a grinding wheel to me.

 

[JONSSTIHL]

here is a pic of my fuel filter in pieces and a pic of the piston from the exhaust side.

let me know what you think of the piston???

 

[mattinky]

Is that a crack in the piston, or just a dark line?

 

[04ultra]

What kinda oil is that thing running??..........




.

 

[JONSSTIHL]

I know seems to me there is a lot of carbon but I've been running it a little rich because I'm scared of blowing the piston. but I got a tach now so I will tune it to spec from now on.

it is using the canadian stihl oil from the dealer mixed 40:1 just to be safe.

that is a scratch in the piston but it looks worst in the pic than in person, it has not reached the ring yet, there is only slight discoloration on the ring at that spot

I found my mityvac and vacuum tested my fuel line and impulse hose. the fuel line slowly leaks vacuum when I flex it but it is so little I'm not even sure that is the problem, and the impulse line holds vacuum so it is good

how about the fuel filter, should I try to clean it in purple cleaner or should I just chuck it and replace with the 350-3500

thanks

 

[Stihl #1]

Use good fuel and mix it at 50:1. The carbon buildup can actually cause piston scoring, and if it is thick on the top of the piston the piston cam hit the top of the cylinder and hammer the rod bearings out of it. Do you have a spark arrester screen in Canada saws? If you do it is probably restricted, which will cause some running problems.

 

[davefr]

That exhaust port looks terrible!!

 

[Lakeside53]

+1 to the above - get your mixture right! You're doing more damage the way it is!.

To clean out the exhaust port, lower the piston, take out the spark plug and gently blow air though it while scraping.

And... use pressure to test your lines - vac can seal up leaks and show not problems.

 

[JONSSTIHL]

lakeside, I was wondering if you have a fuel filter insert on hand 358-1800 could you do a little measuring to see if it could fit my existing filter. Od. Id. and length would be great plus or minus a few thousandths would help a lot.

I scraped all the carbon off of the exhaust port and there is hardly any on top of the piston. there is a little more on top of the cylinder but I don't think it is excessive. I will post a pic of it cleaned out later. I used the piston to block the port then scraped away and sprayed wd-40 to wash away the carbon dust, It worked quite well. the inside of the muffler is pretty bad also but no spark arrestor screen, I drilled out the holes in the inner baffle (same size as stock just to get the carbon out) but I may try to heat it up with a propane torch to burn off the excess, but the muffler isn't as bad as the port.

I re checked my fuel line (still with vacuum) and found that it holds vacuum as well even when flexing but I think I will change it anyways to get the longer one so I can change the filter outside the tank. I need to find some sort of pressure tester anyone have a good source I guess a medical supply place would be a good start (blood pressure tester should do just right)

I got to looking at my carb and I think the previous repair guy may have put the carb kit on wrong. I may be mixed up but I think on the diaphragm side(cover with four screws), it looks like the diaphragm(thin gasket) is on the outside of the gasket. the thick gasket is towards the carb body and the diaphragm is after then the cover is bolted on, I was under the impression the diaphragm was supposed to be up against the body of the carb but I may be wrong on that. on the fuel metering side it is the opposite, the thin gasket is up against the carb body and the thick gasket is after then the cover is bolted on.

thanks guys you've been a great help

 

[Lakeside53]

Nope.. the carb order is correct

Metering side

metering cover
metering diaphragm
gasket
carb body

Fuel pump side

Cover
GASKET
DIAPHRAGM
Carb body

 

[JONSSTIHL]

thanks lakeside, It was a little foggy in my memory and just wanted to double check.

any ideas on the filter insert

mine is .575" OD.,
.400" ID.
and .790"

I'm thinking at this stage of teardown I might as well try a vacuum test, can I block off both exhaust and intake and plug the mityvac in the impulse line.

for the pressure test I may have to go to a shop.

thanks

 

[JONSSTIHL]

as promised here is a pic of the cleaned up port, It isn't perfect but I think it is good enough

anyone know how to post the pic directly to the thread so that you don't have to click on the link.

I'm sure it is something simple but I can't see any other option on the attachment choices

thanks

 

[Lakeside53]

thanks lakeside, It was a little foggy in my memory and just wanted to double check.

any ideas on the filter insert

mine is .575" OD.,
.400" ID.
and .790"

I'm thinking at this stage of teardown I might as well try a vacuum test, can I block off both exhaust and intake and plug the mityvac in the impulse line.

for the pressure test I may have to go to a shop.

thanks

A bicycle pump (careful..) can work fine for the pressure test.

 

[JONSSTIHL]

I got the muffler all cleaned of carbon this morning and decided to do a vacuum test.

I'm getting a certain amount of leak down but I'm not sure if it is good or not. I'm using thin (.050") sheet of rubber to block off the exhaust and intake, I put the muffler and carb back on to seal them up and hooked a hose to the impulse nipple.

my service manual says it should hold between 7.25 and 4.25 psi for atleast 20 seconds and that is about what it does now, in the worst spot, I did turn the crank to find the worst spot. I put 7.25psi of vacuum and it drops down to just above 4.25 psi in about 20 seconds

is this sort of leaking normal. this is my first attempt at a vacuum test so I have no clue what is normal and what is not normal.

I still have to find a suitable gauge for the pressure test. my bicycle pump only starts at 10 psi.

thanks for any info

 

[JONSSTIHL]

one thing I forgot to mention is that the saw does not hold any vacuum for an extended period of time. it bleeds off slowly but it does bleed it completely.

hope that clears things up.

thanks

 

[Lakeside53]

Fix it... replace the seal. I don't care what stihl says.. they should hold vac for a long time if they are any good.

 

[GASoline71]

I have rebuilt a lot of carbs over the years... and never once removed/replaced a Welch Plug. No problems to date with any.

Gary

 

[JONSSTIHL]

thanks for the info guys, I read goat's thread about his 044 and mine hold vacuum for maybe 3 minutes not anywhere close to 24hours

I was going to start a new thread about seals but since we are on the topic here goes

I think I found the culprit. I put oil on the clutch side seal and now it holds vacuum much better and I can hear the oil being sucked in. so I probably should replace the flywheel side at this point also, it isn't much more work other than getting a puller for the flywheel.

the only sad part is I can't get the flywheel off and my dealer is a total loser, he doesn't even know why there are two p/n's and when I asked if they had a puller for the seals both guys behind the counter said, what puller, you have to split the case to change them. (so clueless) too bad they are only 5 min. away. The same dealer wants $600 for a 2152 or 260 and $750 for a 361

sorry just venting about cdn. prices.

how much do these seals go for. they are 5$ for one type and 15$ for the other. I'm assuming I need the 15 dollar ones but I can't remember which was which but I do know I'm looking for the 9638 003 1581

just one more thing, my 025 is leaking bar oil at the connector on the underside and I don't know if it is the oil pickup tube or the o-ring that is leaking. lakeside have you ever seen this and which is more common. the o-ring would be a lot cheaper.

thanks