Maruyama MCV51

[Jughead]

could it be weak lever springs?

 

[Miller Mod Saws]

My 5105 has this problem so I'll tell ya what. Hopefully this weekend I will pop out the tank vent and drill a small hole in the top of the recess and see if that helps. Like I do on a 346xp.
@166 probably has a solution andbinknownhe can answer the carb questions. As he has a really good carb swap number for these that's cheaper than oem. But IDR what it is. Lol.

 

[166]

My 5105 has this problem so I'll tell ya what. Hopefully this weekend I will pop out the tank vent and drill a small hole in the top of the recess and see if that helps. Like I do on a 346xp.
@166 probably has a solution andbinknownhe can answer the carb questions. As he has a really good carb swap number for these that's cheaper than oem. But IDR what it is. Lol.

Here is the fix

 

[Simondo]

Yep, I'm having the same problem. I have 2 of these saws and they both act the same way. Are we sure there is nothing different about these and the Dolmar branded ones? Can someone pm me the IPL and service manual for the 5105...please?
I have done everything I can think of, had both carbs apart a couple times, can't find any metering or any needle valve problems.
The carb is a Zama DM20328A, is that the same one on the 5105?
I have done exactly how Carl described to adjust the low and it did not help.
If I start them daily there is no issue, it is when they set for 3 or 4 days it occurs.
Took the carb off today, been setting for 4 days and gas squirted 3 feet in the air from the fuel line.
I have tried starting from just a no choke dry start 1 pull, just check the plug and it's soaked, turn the saw upside down and gas is dripping out of the cylinder, got me baffled, but I'm no mechanic.
View attachment 67566

Here is a late 2015 Dolmar ps 5105 for comparison ....It has a C1Q DM 20 a (525a) carb on it from factory. Its been left with 1/2 a tank in it for a week..popped on choke 1st pull fired on 3rd after taking choke off. Ran it to warm up and then pulled the carb. Some fuel pressure in the line (didn't burp the tank before pulling the carb) but no gusher. I dont normally leave my saws with much fuel ..if any in.. till im going to use them. Im not sure a bad tank vent will give you much positive tank pressure really ...more a tank vacuum and fuel starvation i would have thought. I figure the pop off pressure in the carb might be worth checking out and the metering arm hight although from factory it "Should" be right !!

 

[Miller Mod Saws]

Here is the fix

Thank you. New ya had a fix. Been running any fast 7900 pipe saws.

 

[Jughead]

Here is the fix

thank ya sir.figured something was wrong.first saw i ever had new that i had to dump gas out of the cylinder.

 

[Simondo]

Here is the fix

Do you have the "GRS Load" number on that spring ? Iv had a look about and am finding springs from 12.5 at 5mm up to 28 at 5mm . Not sure what value the one you have found a fix is .

 

[166]

Thank you. New ya had a fix. Been running any fast 7900 pipe saws.

Pipe saw? I don't know what you're talking about

 

[166]

Do you have the "GRS Load" number on that spring ? Iv had a look about and am finding springs from 12.5 at 5mm up to 28 at 5mm . Not sure what value the one you have found a fix is .

It's a lot stiffer than the OEM Zama spring. It's fixed every saw so far.

 

[Miller Mod Saws]

Pipe saw? I don't know what you're talking about

Dam that Bret!

 

[Simondo]

It's a lot stiffer than the OEM Zama spring. It's fixed every saw so far.

Do you recall any pop off information you measured ? Im thinking of the difference in the "re seat" pressure between the Zama OEM spring and the stiffer spring your fitting. I assume the needle needs more "re seat" pressure to not leak . Many Walbro carbs seem to re seat at 10 psi or a little more recovering from pop off ...These Zama carbs i have not measured myself.

 

[Jughead]

spring is switched.thanks to Greenthorn!
in other news the MCV51 has now increased in price to.....yeap $499.99 with 9 left in stock.

 

[Jughead]

switched spring.filled wirh gas.now pops on choke then runs a second or two with choke off.retune?

 

[Jughead]

anyone have a spare dd adjuster to sell?

 

[Miller Mod Saws]

anyone have a spare dd adjuster to sell?

PAC man one works great as well.

 

[Jughead]

PAC man one works great as well.

alrighty.i thank ya.its raining right now so may try some tubing of some sort til i can get one.

 

[Jughead]

it's alive!And not droolin.thank ya guys.wound up super gluing red butt connectors to the nubs of the adjustment screws to adjust it.just jambed my straight slot in the end.lol

 

[Dolmar Junkie]

anyone have a spare dd adjuster to sell?

Shh, the Environmental Protection Agency will hunt you down like a dog , it's banned for nongovernmental use...
I bought some Chinese drivers but ended up using a dremal to clean up the over abundance of chineesium coating on it . But in the end not to bad for the .99 Penny's that it cost shipped from the house of WhoFlungDung and didn't even take to long to get here....

 

[NCFarmboy]

Amazon carries kits w/all the carb adj. tools. IIRC even has the one for Stihl. Will post link if I can find it again.
Shep

 

[Simondo]

it's alive!And not droolin.thank ya guys.wound up super gluing red butt connectors to the nubs of the adjustment screws to adjust it.just jambed my straight slot in the end.lol

Good news...have you found what carb is on the saw ?