Return to the Tool Shed Forum | Post a Follow-Up

Makita concrete saw

Posted by raydecker (My Page) on
Wed, Jun 13, 12 at 18:30

Hello all, I'm working on a makita concrete saw #DPC7331. The fellow that owns it said that it just stopped running. I find that hard to beleive because the fuel was a brownish color & had water in it. It did not look like a 2 cycle mixture at all. anyway I changed the fuel & plug & it will not even attempt to start. There is spark & compression is 50 psi with 1 (one) pull and 90 psi with 6 pulls. I then put oil in cylinder tried compression again. It was 75 psi on 1 (one) pull & 120 psi on 6 pulls & it still would not fire. I looked down thru spark plug hole at the cylinder walls & I could not see any score marks. Im thinking its all about compression so thats why i'm putting this out to the experts. thanks in advance Ray

Follow-Up Postings:

RE: Makita concrete saw

I Blew My Reply! I replied to the Stihl Cutquik 760 vs
the Makita.

If you have a good blue spark and that amount of compression, IMO, it should try to run if it�s getting fuel.

1. I would suggest priming with some of the fresh premix.
2. If it fires or before, take a careful look in the carb (especially the fine filter and diaphragm�s condition.
3. You might check the Carb adjustments and try and force some compressed carb cleaner into the ports (seat and adjust out 1-1.5 turn for starters and then tune).

Please give a reply on your experimenting and results.
Hopefully someone will jump-in with direct experience with the saw but basics should help you.

RE: Makita concrete saw

From what I understand a 2-stroke will not run on much less than 120 psi of compression. I'd bet that a repair shop would want to replace the jug, piston and rings. That saw sells for about $900. new so proceed accordingly.

RE: Makita concrete saw

Remove the muffler and have a look at the piston skirt, it is likely scored. Most cut off saws lead a hard life especially if the operator is less than religious about air filter maintenance.

RE: Makita concrete saw

The inspection through the exhaust port (as romore mentioned) with the muffler remove is a better view to inspect from. From this view you will get a better view of the cyl walls and rings.

Low compression has confused me on many newer 2-cycle engines due to how well they will run with the compression. I feel in many newer 2-cycles there are low compression modes built into them and the compression increases when the engines start. In some cases you know there is a compression release button and the engine will fire at low comp which forces the button back out to increase the comp. How Low Is Too Low since some engines are designed to start low?

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Tool Shed Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here