Husqvarna 445 clammy build

I have a metal plate that bolts over the muffler opening with rubber inner tube piece that seals it. I have a hole in that setup that one of the skinny tapered plastic probes from the mityvac kit just friction fits into. Can't see that in the pic. The chartreuse and light blue plugs came in the mityvac kit too. I'm glad I purchased the whole kit when I got it cuz those rubber plugs sure come in handy. I did blow one of the chartreuse plugs out of the intake manifold when pressure testing it. You may be able to get a variety of rubber stoppers from the hardware store. Golf tees are handy to have around also.

 

I was able to get the carbs swapped today between this whacky 445 and the 450 that I'm doing the muffler mod.

IT IS THE CARBURETOR that is bad... The 445 rips with the good carb on it from the 45o.
The 450 sucked with the crappy carb on it. I had to do it both ways to fully remove any self doubts since my man card is in restricted status over this saw...

This means that the 2 new chinesium carbs I got are also junk (I'm sure many of you could have told me that already). The aftermarket kit that I rebuilt the original OEM carb that didn't have the welch plugs also didn't do the trick. I chased my tail on this saw and now I have to beg to get my man card back...

I have a new OEM ZAMA RB-145 carb kit (including welch plugs) on the way to hopefully work full magic on the original OEM carb...

LESSON LEARNED...

 

It’s always great to get to that ah-hah moment!

I bought a carb off Kevin for a problematic issue on my sons 365sp. Put the carb on (it was brandy new) and the saw would not idle no matter what I did. He said he bought a whole bunch on ebay and one other guy had the same issue. It was an oem Zama so already made you know where.

 

I want to click a "love" button for the comment that you got your saw problem figured out! Way to go! I have a threaded piece with o'ring that replaces the spark plug and has a nipple on it for the mityvac hose to connect to. I will look at the hardware store for a couple rubber plugs. I like your set up. I purchased a cheaper version mityvac many years ago just for one person brake bleeding.

 

Glad to hear of the progress...now, I hope this gremlin doesn't get loose in your shop...

 

I have similar. I broke apart a plug and JB Weld’d a fitting to it so I can attach MightyVac. Works great.

 

Wow, that was crazy ...

 

"Figured out" is one thing... Getting this carb fixed may be another...

Hoping the OEM kit will allow me to get everything cleaned out and I get the welch plugs sealed back in well... I've cleaned dozens and dozens of carbs over the years but I've only ever had to deep dive this far on a couple before. Both of those were fairly new OPE that had sat for more than a year (maybe longer) with pump gas in them that varnished and corroded in the carb. I had to pull the welch plugs to get them cleaned out good enough to get 'em back into running condition. This saw is the first time I ever went with the "replace" the carb route and it busted my 6@11$.

I will be much more diligent ensuring that I'm getting OEM carb rebuild kits that include all the welch plugs in the future.

 

I've been digging more into the internal workings of carbs in my spare time. I've never really dug to deep before because a simple cleaning or carb kit has usually restored normal operation and I haven't given it much thought other than spay a little carb cleaner and change a brittle diaphragm or two and Voila... works like a champ again. A couple I even had to take out the welch plugs and clean gunk out of the inner passages.

This carb however is causing me to expand my horizons and must have a problem with one of the check valves. Zama says toss it and replace the whole carb although they sell check valves and nozzles. I'm going to mess around with the 3 carbs I have and see if I can get at least one working now that I've done some more reading and have a little better understanding of how these little magic boxes with holes in them really works.

This explanation is pretty helpful. https://www.zamacorp.com/uploads/1/20181114/0cb5015de04ea27d66b722f5e3e987f9.pdf

another helpful read for us carb part swapper hacks...
MS 360 ZAMA carb rebuild - Chainsaw Collectors.se

.

 

Had some time this morning, went through the 3 carbs. I took out the welch plugs in the OEM carb and cleaned the filthy passages under them, I was hopeful...
checked pressure and vac on all the check valves although I couldn't figure out how to check pressure on the high nozzle check valve since the nozzle assembly of this particular nozzle doesn't feed directly through like the one in the write up I shared above.

I put the OEM carb on and it started, idled and ran great for several cuts. I shut it off and it wouldn't re-start. It would only re-start holding the throttle wide open and it would cut fine, but as soon as it went below half throttle it would stall out. I'm assuming this is the high nozzle check valve hanging open causing this. Being a rookie at this carb stuff may have me barking up the wrong tree though.

More playing with the other carbs to come.

 

That's what people forget about carbs...its not just the fuel passages that have to be open...its the air passages too. Same with electrical...don't just check for power, gotta have neutral/ground too.
My experience has been that the air side being fouled up is usually what the culprit is on carbs that act up after the first cleaning...but then diaphragm carbs can be finicky lil beasts, even when things are right too!

 

Got the carb switched to one of the other ones tonight. It started right up and sounds good, but it was dark out and I didn't get it in wood yet to see if it performs under load. Fingers crossed.

Moving on to another project but I'll get this one finished up soon now that I'm getting the carburetors figured out in my head.

 

Nice. I'm about to wrap up the 241 then, on to making two Homelite 150's into one.

 

I put it in some wood and it runs pretty good.

I did some practicing on the carb with the bad nozzle this evening. I'll do the good one when I get some more time and see if that helps out any. By the looks of the more open space through the carb I would think it should make a little difference.

Before trimming the stuff out of the way.


with a little trim!!!


Yeah, I know, it isn't the thing of beauty that I would hope for, but it looks way more open through there now... Hoping to get a little better with a couple more before I open up the carb on my G288 also...

 

It can't hurt performance I'm betting.

 

Every little bit helps.

 

Yep.