Dolmar 5105 starting issues

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Hi guys,

Well, @fordf150 came through with the parts. They shipped the next business day, and arrived two days later. They were exactly the right part. Thank you!

After a few evenings of trying to get it to work, i finally got it done last night.

It seems I wasn't getting the gap between the coil and flywheel just right. After disassembly and reassembly about 20 times, with spark and run testing mixed in, I finally got the gap where it runs well. Two sheets of paper seems to be the best, a thick business card, thin business card, and three sheets of paper all seemed to give no or to little spark. I almost have up today and took it to the shop, glad I didn't.

The coil and flywheel don't seem to be hitting at all.

I also ran the spark plug wire behind the ground wire and spade clip, but I can't remember if it was in front or behind when I disassembled. It seems to fit this way, and seems better protected. Let me know if I should change that.

After messing with the carb settings, when the issues started, I had to retune as well. I attached a video of the retune, sorry it's long and poor quality. It seems a little touchy on the high setting when I try to get it dialed in at 13,500 rpms. I will do a final check once I get it hot and in some wood.

Let me know if it seems I got the settings wrong or if something doesn't sound right.

 
I always send this video when people ask. It seems to be able explain to the beginner how to get the carb within the ballpark to run right.

Turn the idle screw in until the chain starts to move, then back it off slowly until it stops. That should be all you need to do with the idle. Next, do what it says with L. Then nail the throttle several times and see if throttle response is good. Also, you want it to rapidly return to idle without the chain spinning on it own.

Hope this helps!

Cheers, :cheers:
 
From my notes for the 6401 13,200 rpm is max. Pretty sure the 6421 is the same, 13,500 rpm seems high.
 
I think I remember reading that some of the 5105's had 13500 coils and the newer ones are limited to 12500 or 12800. The 6400, 6401, 7900 and 7901 are 13500 coils. The 6421 and 7910 are 12800 limited coils, I believe.
 
I think I remember reading that some of the 5105's had 13500 coils and the newer ones are limited to 12500 or 12800. The 6400, 6401, 7900 and 7901 are 13500 coils. The 6421 and 7910 are 12800 limited coils, I believe.

Hi guys,

Thanks for the input.

I could be wrong here, but I think the 5100s was at 14,500 max RPM.

According to Dolmar, via the attached link and the owners manual it is 13,800 max rpm - http://www.dolmarpowerproducts.com/productcatalog/chain_saws_gasoline/ps-5105/index.html

I found a couple other posts here saying 13,800 were the max. Even when set this way on the last coil I was running a little rich.

Can anyone confirm what I should be setting this at?

I am glad to tune in the wood too, but I am always concerned I will lean it out to much. The tach, atleast keeps me from going to lean, unless I don't know what the setting should be :)
 
5105's are limited at 13800.
6400/6421=13200
7310/7910=12800

13500 even for break in is a tad rich, if they werent coil limited they would tune around 14-14100 so you could go another couple hundred rpm without worry. sneak up on the 13800 as close as possible and leave it there.....you'll still have 200-300 rpm of cushion.
 
5105's are limited at 13800.
6400/6421=13200
7310/7910=12800

13500 even for break in is a tad rich, if they werent coil limited they would tune around 14-14100 so you could go another couple hundred rpm without worry. sneak up on the 13800 as close as possible and leave it there.....you'll still have 200-300 rpm of cushion.

Thanks guys!

I am always amazed by the generosity and knowledge of the guys on this site.
 
Hi guys,

Well, @fordf150 came through with the parts. They shipped the next business day, and arrived two days later. They were exactly the right part. Thank you!

After a few evenings of trying to get it to work, i finally got it done last night.

It seems I wasn't getting the gap between the coil and flywheel just right. After disassembly and reassembly about 20 times, with spark and run testing mixed in, I finally got the gap where it runs well. Two sheets of paper seems to be the best, a thick business card, thin business card, and three sheets of paper all seemed to give no or to little spark. I almost have up today and took it to the shop, glad I didn't.

The coil and flywheel don't seem to be hitting at all.

I also ran the spark plug wire behind the ground wire and spade clip, but I can't remember if it was in front or behind when I disassembled. It seems to fit this way, and seems better protected. Let me know if I should change that.

After messing with the carb settings, when the issues started, I had to retune as well. I attached a video of the retune, sorry it's long and poor quality. It seems a little touchy on the high setting when I try to get it dialed in at 13,500 rpms. I will do a final check once I get it hot and in some wood.

Let me know if it seems I got the settings wrong or if something doesn't sound right.


Coil gap it usually just under 0.01", but some purists want 0.009". I use a feeler gauge, but some say a business card is awfully close. I tend to trust my feeler gauge. Anyway, this looks good. These saws are awfully hard to criticize when they run right. That's why I own own a Makita 520i that runs and cuts like a bandit.
 

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