Need help with ms361 carb mod/ some other ?'s

[TimberTramp420]

I have a ms361, all I've really done is clean it up, new piston, modified exhaust, modified intake, new filter, plug. Ive seen stumpys carb mod and Im looking to do the same my first question is I dont plan on getting a big bore kit for a year at least so is a carb mod not necessary, if it is possible can someone point me in a direction with pictures on how to drill out the hole for the carb I believe its the ms 290 or 380 carb and does anything else need to be changed besides the tune of course but what about timing?

some other questions if any of you 361 lovers could help me out
1. is the 361 a stratto saw
2. is oem ms361 coil limited or unlimited
3. how much did ms361's orginal sell for
4.when was the ms361 released/discontinued
5. do some dealers stihl have access to them


Also is my coil bad?(wanted to make sure before I replace it)
My saw sometimes dies and wont start till you let it cool or at least sit for 5 minutes, it really makes me mad so if someone could help id appreciate thanks again

 

[cgraham1]

Amazing what you can find with a Google search...

http://www.arboristsite.com/community/threads/project-stumpbroke-ms361.221405/

It was the only quad port saw Stihl made before they stumbled into the "strato" area.

It's unlimited.

I did upgrade to a bigger carb. I ended up using one off of a MS390. I started out using one off of a MS460 but it had idle issues the same as the 361 I have for myself. Once I installed the 390 carb all issues were gone on both saws.
There are few minor mods that need to be done to the 390 & 460 carbs to use them on a 361. The choke shafts, and both covers need to be swapped also an impulse passage needs to be drilled into the body.
I use both of the covers off of the 361 carb (Right)
note: pic was take after the choke shaft had been swapped.

This pic shows the difference in the venturi size.

These pics show the passage that needs to be drilled for the impulse line

Other than that it is a direct swap.

It's just a few mm into the body, you have to drill in two places to get them to connect.

The hole on the upper right hand side needs to be drilled.Then drill the passage that the screwdriver is pointing too until they connect.

The choke shaft does have to be cut (widened) to accept the larger butterfly of the bigger carb. other than that it's just a matter of swapping them out.

 

[old-cat]

You're better off to use the OEM cylinder ONLY. I put an MS440 carb on my pro ported MS361 and it did NOTHING for performance.

 

[Terry Syd]

Oh bugger, I wish I had never laid eyes on that 460 carb...17.45mm

Has anybody got a 460 carb that they could open up and take a picture of the metering chamber? I sure would like to see how it is configured. I think it may be an 'emissions carb' - and if so, that can be fixed.

 

[mdavlee]

Oh bugger, I wish I had never laid eyes on that 460 carb...17.45mm

Has anybody got a 460 carb that they could open up and take a picture of the metering chamber? I sure would like to see how it is configured. I think it may be an 'emissions carb' - and if so, that can be fixed.

What't the venturi size on the zama on the 7900?

 

[Terry Syd]

17mm, but it also has been flowed on a bench. The 460 looks like it may have taken a hint from Zama and relocated the discharge nozzle. If you take a look at the difference in the venturis of the 290 carb and the 460 carb you can see the difference.

The 290 carb comes directly in and you get those two high velocity areas (turbulence) on both sides of the nozzle. The 460 carb is angled in and the area to the left of the nozzle is opened up so the area of turbulence is smaller. On the right side it is the same thing, but the open end of the nozzle is sitting closer to the edge of the venturi where it has a stronger signal. I'd expect the 460 carb to both flow better and have better metering.

Never mind about opening up a carb to take pictures, I just bought a 460 carb on Ebay for $25.

 

[mdavlee]

I have a 460 here with a stock carb. Wonder if there would be gains to be had in it?

 

[TimberTramp420]

Thanks c grham but is there any more info on what exactly needs to be done i dont just wanna go drilling a hole threw my carb, and are we pretty much saying its a pointless mod since not ported or still do-able?

and what does quad port mean if someone could give me a good def.

 

[Terry Syd]

I have a 460 here with a stock carb. Wonder if there would be gains to be had in it?

Let me have a look when this 460 carb comes in. The carb I bought is likely a Chinese knock off. What I've found so far with the Walbros, is the Chinese take a cheap short cut and drill the second air bleed at 90 degrees instead of a separate drilling rig using a different angle. If it does affect the throttle response, I can always work around that by filling the Chinese hole with GB Weld and drilling the second air bleed by hand. However, I may be able to get around it with changing the spring or just the pre-load on the spring.

I was going to do a thread about modding the HD5 carb for the Walbro guys, but bugger that, if the 460 carb is a better Walbro to do the work on, then I'll use that carb. The tricks on the Walbro will be the same no matter which series of HD they have, but this carb is going on my 'sleeper', so I might as well use a Walbro carb that I think may have better potential than the Zama.

I wish I had a flow bench. I'd expect that a bit of GB Weld next to the discharge nozzle on the Walbro 460 carb could get it to flow even better.

 

[old-cat]

Thanks c grham but is there any more info on what exactly needs to be done i dont just wanna go drilling a hole threw my carb, and are we pretty much saying its a pointless mod since not ported or still do-able?

and what does quad port mean if someone could give me a good def.

Quad port refers to two transfer ports on each side of the cylinder.

 

[TimberTramp420]

lmao corn flabbit what do I have to do to the carb and is it even worth it any gains at all?

 

[old-cat]

lmao corn flabbit what do I have to do to the carb and is it even worth it any gains at all?

I still have my modified carb, you can buy it from me but it's a total waste of money. Zero gain.

 

[MillerModSaws]

Did u read the link they posted above. It's pretty descriptive. And drill it so it looks just like your 361 impulse hole. A set a calipers will be handy.

 

[blsnelling]

Mod your muffler, re-tune, and be done with it. Otherwise, send it off to be ported.

 

[cgraham1]

lmao corn flabbit what do I have to do to the carb and is it even worth it any gains at all?

Did you read Stumpy's thread? It looked like he explained it in there. With pictures.

I don't have the carbs in front of me to compare

Mod your muffler, re-tune, and be done with it. Otherwise, send it off to be ported.

Stock MS361 was the most disappointing saw I've ever run. I wish I would've tried a muffler mod on mine before I decided to sell it.

 

[nikb47]

I have a ms361, all I've really done is clean it up, new piston, modified exhaust, modified intake, new filter, plug. Ive seen stumpys carb mod and Im looking to do the same my first question is I dont plan on getting a big bore kit for a year at least so is a carb mod not necessary, if it is possible can someone point me in a direction with pictures on how to drill out the hole for the carb I believe its the ms 290 or 380 carb and does anything else need to be changed besides the tune of course but what about timing?

some other questions if any of you 361 lovers could help me out
1. is the 361 a stratto saw
2. is oem ms361 coil limited or unlimited
3. how much did ms361's orginal sell for
4.when was the ms361 released/discontinued
5. do some dealers stihl have access to them


Also is my coil bad?(wanted to make sure before I replace it)
My saw sometimes dies and wont start till you let it cool or at least sit for 5 minutes, it really makes me mad so if someone could help id appreciate thanks again

What did you modify on the intake?

The ms 290 or 390 carb is the one you want. They are the same with different size H jets. You really don't have to drill the carb if you just get the 390 impulse line and 044 intake boot (less restrictive) my ms361 already had the hole on the tank/handle where the impulse line comes in.

I don't know if it made a lot of difference swapping carb and intake boot because I did port and squish work at the same time. But it does run out pretty darn good now.

Good luck

 

[TimberTramp420]

Just drilled more holes for air to intake threw, but are there any performance gains from the 044 elbow+ 290/390 carb and how jank will the choke have to be

 

[Wood Doctor]

OP asked, "3. how much did ms361's orginal sell for?"
-------------------------
Ans. About $650 with sales tax. I also bought the carrying case, so I spent a little over $700 in early 2008. It's still my favorite and most operated chainsaw.

 

[TimberTramp420]

So again any performance gains on the 290 carb and 044 elbow or waste of time?

 

[old-cat]

AGAIN, it will get you NOTHING!