Makita/Dolmar 6400 - Starting Procedure?

[Jack_Shaft]

Just bought a good used Makita 6400.

This my first larger Dolmar and I am having some trouble starting the thing. Seems like it will run for a few secs and start to warm up but then it falls on its face.

I have a bunch of other Stihls and they usually warm up nice on fast idle, then I can blip the throttle a time or two to break it out of choke mode and it runs good from there on.

What's the trick to starting the 6400? Full choke to start, then half choke, or cut the choke altogether? It's freaking cold here, in the range of -15 to -20C now, but the saw is stored in a garage that usually maintains -5C or so.

Also what is the max RPM of this saw?

Any input would be appreciated.

-Rob

 

[PES+]

2 thoughts

What oil ratio are you using and what brand oil?

Also you need to richen your carb settings for colder air operation

Colder=denser=more air ........so more fuel

 

[osb_mail]

dolmar

I used to have a dolmar the carb was out of adjustment more than in .I think it was a 115I .It was a good saw when i could keep it in adjustment.

 

[sugarbush]

Just bought a good used Makita 6400.

This my first larger Dolmar and I am having some trouble starting the thing. Seems like it will run for a few secs and start to warm up but then it falls on its face.

I have a bunch of other Stihls and they usually warm up nice on fast idle, then I can blip the throttle a time or two to break it out of choke mode and it runs good from there on.

What's the trick to starting the 6400? Full choke to start, then half choke, or cut the choke altogether? It's freaking cold here, in the range of -15 to -20C now, but the saw is stored in a garage that usually maintains -5C or so.

Also what is the max RPM of this saw?

Any input would be appreciated.

-Rob

turn L jet ccw a little, max rpm 13500, should be set on a tac.

 

[Jack_Shaft]

What oil ratio are you using and what brand oil?

Also you need to richen your carb settings for colder air operation

Colder=denser=more air ........so more fuel

I'm running Castrol mineral oil, TCW-3 rated @ 40:1. Same stuff I use in my 2-stroke snowmobiles around this area.

I'm doing some adjustments now... added more fuel to the top end and inverted the carb-to-cylinder window so more warm air will flow into the carb area for a quicker warm-up.

 

[Jack_Shaft]

turn L jet ccw a little, max rpm 13500, should be set on a tac.

Thanks, Makita actually has very good downloadable .pdf owners and parts manuals on their website, I found the full array of specs there.

With those in hand, I should be very much OK with my new saw.

 

[Big Woody]

The choke has a fast idle that stays on when the choke lever is pushed back in.

I Pull the choke, pull til it fires, push in the choke and pull til it starts.
Hitting the trigger deactivates the fast idle once it starts running.

I have 2 6401's and a 7900.

 

[drmiller100]

on mine, i pull choke full out, pull the rope twice at which time it fires, then push the choke back in and she is at high idle. stab throttle, and she is cold, but kind of trying ot idle at low speed.

almost for sure your low speed jetting is too lean.

you are having the classic symptoms.

It is used, so someone probably screwed it up. Turn the low speed out a quarter turn, see if it is better. that is counter clock wise.

if no differnece, or some better, then give her another quarter turn.

it is kind of weird ot learn which way to go. when she is REALLY cold, if it is too rich it will idle just fine, but not idle once it warms up. If too lean, it is fine on warm days, but has troubles on cold days like you are having now.

 

[Jack_Shaft]

Ya, I am having difficulty making the transition from idle to engagement of throttle; it will idle half decent now, but I always get a bog when trying to come off of idle and onto the throttle.

One thing I did notice today when I had the air cleaner cover off was that the carb seems really loose. It didn't seem like it was sucking air anywhere when I moved it around a fair amount, but if I pushed it to one side a lot, it would die out. Perhaps I have an air leak there. I have the L speed screw turned out (CCW) 2.5 turns now and it still feels lean, so I must have an air leak in there somewhere.

I'll have a look at the carb boot and clamp tomorrow. I had an MS260 that was acting the same way recently and when I investigated further, the intake boot between the carb and the cylinder was installed wrong and it was partially pinched off.

Hopefully once I tighten up the carb clamp the lean bog at low speed will go away.

What are you guys running for L & H adjustment, i.e. # of turns out from seated?

 

[Big Woody]

On one of the 6401's I had the H opened up all the way. It had the plastic limiter caps on both on the jets. I took a hot screwdriver from the MAPP torch and melted off the lugs to I could adjust at will. Then I richened up the H screw.


Mine didn't have the problem yours does.

 

[drmiller100]

sure sounds like an air leak, or too lean an idle.

take an eye dropper and drip gasoline all around the intake. usedtobe you could use carb cleaner, but no more.

ether probably still works.

 

[blis]

yeah, you got an airleak....

if carb screws need to be opened more than 2 turns theres is something wrong with saw, in this case, its airleak...

 

[Jack_Shaft]

Any known areas that the carb boot will leak?

 

[PES+]

Check the two caarb mount screws

The two screws that go through the air horn and carb screw into two square nuts on the mount flange these need to be tight. Also check the clamp that holds the rubber boot to the cylinder. If the clamp is loose remove the boot and clean the mount on the cylinder and the inside of the boot and re-install. If the clamp loosens it sucks dirt and sawdust into the sealing area and will not seal well.

 

[Hard Knocks]

yeah, you got an airleak....

if carb screws need to be opened more than 2 turns theres is something wrong with saw, in this case, its airleak...

That is not necessarily true on all saws with limiter caps. Some Husqvarnas have factory settings of 2-3/4 turns on high and 2 turns on low. I have also heard of this on others. I don't know about Dolmars but you should check the service manual for the factory settings.

 

[blis]

That is not necessarily true on all saws with limiter caps. Some Husqvarnas have factory settings of 2-3/4 turns on high and 2 turns on low. I have also heard of this on others. I don't know about Dolmars but you should check the service manual for the factory settings.

are you sure? since far as i can remember the factory setting for husky is 1 turn on H and 3/4 on L...

 

[SWE#Kipp]

are you sure? since far as i can remember the factory setting for husky is 1 turn on H and 3/4 on L...

My 346xpg did have 2 turns out before I cut the caps of, And it did not turn any greater rpms like that ,,,,,, max rpm with a 13" b/c was 12500

 

[Hard Knocks]

are you sure? since far as i can remember the factory setting for husky is 1 turn on H and 3/4 on L...

Yes 100% sure. Our general rule of thumb is that if it has limiter caps and you don't know the settings - look them up. The Husqvarna 335XPT Is H3-1/2 L1-3/4 The 334, 336, 338's are 1-1/2 both. The 570 L1.5 H2. The 575 L1.5 H3.

Jack_Shaft's saw may very well have an air leak or fuel problem, but I would not come to that conclusion from the needle jet settings alone.

 

[blis]

Yes 100% sure. Our general rule of thumb is that if it has limiter caps and you don't know the settings - look them up. The Husqvarna 335XPT Is H3-1/2 L1-3/4 The 334, 336, 338's are 1-1/2 both. The 570 L1.5 H2. The 575 L1.5 H3.

Jack_Shaft's saw may very well have an air leak or fuel problem, but I would not come to that conclusion from the needle jet settings alone.

oh well, cant win always....

but anyway, when the saw aint responding to carb changes well its definately airleak...

 

[Jack_Shaft]

This is a great convo guys

Now what about the stock carb settings for that 6400?

H/L ?