Mastermind meets the Dolmar 7900

[o8f150]

Speaking of your 372......I'll box it up today. It's pushing 175psi and is very strong. I've ran several tanks of fuel through it and really like the way it turned out. I do apologize for having it so long, though I did get some great info out of it and the other one I built along with it.

i feel so used and abused now,,, we all know you just wanted to cut some firewood for yourself:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:
it not a problem randy,, glad you got some info with it,, that makes it worth the wait

 

[Mastermind]

i feel so used and abused now,,, we all know you just wanted to cut some firewood for yourself:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:
it not a problem randy,, glad you got some info with it,, that makes it worth the wait

I counted the saws in my shop a little while ago. There's 38 of em.

If I hadn't needed the shelf space I woulda kept it longer. :hmm3grin2orange:

 

[o8f150]

I counted the saws in my shop a little while ago. There's 38 of em.

If I hadn't needed the shelf space I woulda kept it longer. :hmm3grin2orange:

if wanted to keep it then it must have turned out good,, not bad for a 225.00 saw:biggrin::biggrin: yes i know,, just rub it in:hmm3grin2orange::hmm3grin2orange:

 

[Hedgerow]

opcorn:

 

[wendell]

looks like it should be a smoking saw when you are done,, what the hell am i saying,,any saw that you have built has been a smoking saw,,but i bet that pos dolmar won't keep up with my 372

Time to go back to your snackies. :msp_thumbdn:

 

[Hedgerow]

Time to go back to your snackies. :msp_thumbdn:

Hey Wendell, I need to borrow your Makita... Not for long though... And I promise to put it back together when I'm done with it...
:hell_boy:

 

[Isna]

opcorn:

 

[Andyshine77]

I checked numbers on the new top end last night. It will end up with 162 duration after machining the jug. It has 30 degrees blowdown now. :msp_w00t:

Duration sounds good, I'd like a few degrees less but you're OK. You could also get away with a LITTLE less blowdown. Squish can be a bit tight with theses saws as well, they seem thermally efficient as they don't like to heat up, even with pretty high compression.

 

[wendell]

Hey Wendell, I need to borrow your Makita... Not for long though... And I promise to put it back together when I'm done with it...

I'll get back to you on that.

 

[mweba]

I'll get back to you on that.

If you let him borrow it......is ear protection included?

 

[Hedgerow]

If you let him borrow it......is ear protection included?

Awe... That saw is quiet compared to my 372.... Wait till I let you run that one... Bring yer ear plugs... :hmm3grin2orange:

 

[Mastermind]

Well fellers I lost a whole day due to my lathe taking a crap on me. It took a while to find it but one of the slides on the carriage had cracked. This caused it to chatter badly. I got it fixed and re-tuned......finally. :msp_thumbdn:

 

[Jakers]

I counted the saws in my shop a little while ago. There's 38 of em.

If I hadn't needed the shelf space I woulda kept it longer. :hmm3grin2orange:

with another one on the way :msp_thumbup:

 

[cutmaster]

Another One Bites the Dust ~

This is our second Dolmar PS 7900 that got stuck-up....
This one we even opened up the muffler a little bit and ran it a tad rich....
Is running 5 gallons a day through these saws causing this?
View attachment 218239
:msp_mad:View attachment 218240
View attachment 218241
:taped:View attachment 218242

 

[srcarr52]

This is our second Dolmar PS 7900 that got stuck-up....
This one we even opened up the muffler a little bit and ran it a tad rich....
Is running 5 gallons a day through these saws causing this?
View attachment 218239
:msp_mad:View attachment 218240
View attachment 218241
:taped:View attachment 218242

Having scoring on even the intake side suggests that it was run with a low oil or no oil mix. The combustion chamber and spark plug have good color so it was not a lean seizure. I bet that cylinder can be saved with muratic acid.

 

[nmurph]

This one we even opened up the muffler a little bit and ran it a tad rich....

Did you have it four-stroking good at wide open throttle?

 

[Jacob J.]

Having scoring on even the intake side suggests that it was run with a low oil or no oil mix. The combustion chamber and spark plug have good color so it was not a lean seizure. I bet that cylinder can be saved with muratic acid.

Maybe the gas was a bit stale?

Cutmaster- do you have a bulk tank for gas that you use? People with bulk tanks sometimes have the gas sit a while and it starts to go stale.

Remember too- Stabil and similar products help to keep gas chemically stable but they do not protect or preserve the octane rating of gas.
Gas starts losing its' octane rating steadily when its stored.

 

[Hedgerow]

This is our second Dolmar PS 7900 that got stuck-up....
This one we even opened up the muffler a little bit and ran it a tad rich....
Is running 5 gallons a day through these saws causing this?
View attachment 218239
:msp_mad:View attachment 218240
View attachment 218241
:taped:View attachment 218242

Plug looks good... But odd that damage would be done on the intake side...:msp_confused:

 

[blsnelling]

Do you fire them up in that MN cold and throw them straight in the cut? Do you retune for the cold weather?

 

[8433jeff]

Only the second day of winter here, Brad; bet its been colder there than the lower half of MN.
If hes north of that, then maybe. How do you run five gallons of fuel through it a day, isn't that like 15 tanks?