Author Topic: Nemisis MS460  (Read 1180 times)

0 Members and 0 Guests are viewing this topic.

Offline Al Smith

  • Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 2779
  • Karma: 181
Re: Nemisis MS460
« Reply #10 on: May 14, 2012, 07:11:24 pm »
That sounds typical of an intake boot . The rascals can get torn on the under side where you can't see them .I managed to tear up two on the souped up 038 Mag before I found the cause which was the top left hand side anti vib mount .My Lawd would that thing run though . The thing wouldn't  act up until you got the R's up in a cut which probabley opened up the crack and gave it more air .Somehow it sucked enough gas to keep from toasting the piston .How I'll never know .

Probabley what saved it was I thought the carb was acting up and I had it set extremely rich .Got extremely lucky that time .

Offline joe_indi

  • 5 cube
  • ***
  • Posts: 134
  • Karma: 42
  • Location: Cochin, India
Re: Nemisis MS460
« Reply #11 on: June 13, 2012, 01:13:27 am »

Saw now runs turned on l/r sides.  Problem now is surging when in bucking position.

Sorry, I came in a bit late on this. What you mentioned seems typical of a bad jet valve (check valve) in the carb. Air blowing into the metering chamber through a badly holding jet valve will lower the fuel level in the metering chamber.
You hold the saw sideways, it runs lean and rpm goes up. You hold the saw the some other way, the saw runs rich and dies.
You try to rev and the engine sounds like it is running out of fuel.
If you had not mentioned the above symptom, I would have told you to check the ignition system, viz. the ignition module and the short circuit wire.
An ignition module that is on its deathbed will show all signs of being healthy, except when the saw starts up, it will just supply current for a few sparks then go on the blink. Till to try to start up again.
The short circuit wire (the black one ) could have lost a bit of insulation and could earth out the current when the bare wire comes into contact with the body.


Offline mdavlee

  • 5 cube
  • ***
  • Posts: 138
  • Karma: 4
Re: Nemisis MS460
« Reply #12 on: June 13, 2012, 07:04:39 am »
I had a 460 that didn't run exactly right. The carb had a bent needle and was leaking air around it.

Offline Al Smith

  • Moderator
  • Nitro Hotsaw
  • *******
  • Posts: 2779
  • Karma: 181
Re: Nemisis MS460
« Reply #13 on: June 22, 2012, 06:48:06 am »
I'm not sure exactly which style ignition coil is used on that model .However on an 042 which uses a self advancing coil I once had a similar problem .

The way that thing works is through the electronics within the circuitry as the engine reached a certain RPM it would self advance .In that case the modual would cycle on advance ,then to retard .About drove me nuts until I changed the coil with a known good one .

I had the same or almost same thing happen on a Briggs and Stratton 18HP engine .Except the modual would stay on advance thus firing early and when warm it was impossible to start  .It nearly let all the magic smoke out of the starter .Not good .


Related Topics

  Subject / Started by Replies Last post
9 Replies
Last post November 18, 2011, 05:22:28 pm
by Al Smith
17 Replies
Last post February 12, 2013, 07:48:58 am
by bassman
1 Replies
Last post October 22, 2013, 09:19:16 pm
by 660magnum
17 Replies
Last post January 02, 2015, 05:33:09 am
by man of stihl
0 Replies
Last post May 16, 2015, 10:41:19 pm
by blueberrymuzik
101 Replies
Last post September 26, 2015, 01:48:48 pm
by Cut4fun .
29 Replies
Last post September 28, 2015, 12:21:17 pm
by aclarke
9 Replies
Last post October 09, 2015, 03:04:41 pm
by aclarke
3 Replies
Last post January 01, 2019, 03:56:14 pm
by Big_6
5 Replies
Last post March 09, 2022, 06:22:18 pm
by 3000 FPS