Dolmar 5105 Problem

[uziduzit9mm]

Hello, I ran into a real head scratcher with this one. This 5105 EZ start came to me with a blown up top end. I decided to put the less expensive DS510 Cylinder and piston into it, since I was told it would work, with just less RPMs and less power. The cylinder kit is Makita part # 179-130-215. Cyinder was correctly installed and compression tested at 157PSI. Engine was also pressure vacuum tested, no seal leaks. Carb was rebuilt, pressure tested, no issues. I even had another brand new carb laying around that I swapped in just in case. She just wont fire. I also had another flywheel laying around I think from a 510, I swapped that in since it has a different magneto position than the one that was on it and I thought it could be a timing issue. I also tried 3 different red coils I had lying around. Saw is getting spark with all three coils, and its getting fuel, but it will not start. I still think its a timing issue, both flywheels do not have any part numbers on them, neither do the red coils. I was thinking of ordering a black 510 coil but I really do not want to start throwing parts and money at this thing blindly. Anyone have any ideas?

 

[link]

So you get a spark, and if you remove the spark plug an put a little fuel in there - you still dont get a fire?

 

[uziduzit9mm]

So you get a spark, and if you remove the spark plug an put a little fuel in there - you still dont get a fire?

I tried putting fuel into the cylinder and sprayed starting fluid on the air cleaner, no ignition.

 

[pioneerguy600]

Did you remove the flywheel off the crank? I have seen many shear the key when reinstalled as they are not torqued down tight enough. A sheared key will affect timing, the will still have spark but its at the wrong time.

 

[uziduzit9mm]

Did you remove the flywheel off the crank? I have seen many shear the key when reinstalled as they are not torqued down tight enough. A sheared key will affect timing, the will still have spark but its at the wrong time.

I did I removed both flywheels several times ion and off trying to see if the timing is different on them. which it is. The groove is in perfect shape on both wheels.

 

[mudfly]

Impulse problem? Is the plug wet?

You need to figure out if it is fuel or spark.

How are you testing for spark?

 

[pioneerguy600]

I did I removed both flywheels several times ion and off trying to see if the timing is different on them. which it is. The groove is in perfect shape on both wheels.

Ok, that`s good, one step done, if the sparkplug is wet all the time then the saw is flooded, too wet to fire. It needs to be dried out and then the carb needs to be looked at, inner parts examined for stiff diaphragms that hold the needle off its seat or debris under the needle.

 

[uziduzit9mm]

Ok, that`s good, one step done, if the sparkplug is wet all the time then the saw is flooded, too wet to fire. It needs to be dried out and then the carb needs to be looked at, inner parts examined for stiff diaphragms that hold the needle off its seat or debris under the needle.

I ran two different carbs, one is brand new. 9m checking for spark with plug out and grounded to cylinder.

 

[user 147613]

I had a similar issue with 5105 with ez start. My problem was the coil is different on the ez start model. Flywheels are the same but the key in the crankshaft was at 3 at tdc. I had to have the black coil. I also tried the red coils before i figured it out.

 

[uziduzit9mm]

I had a similar issue with 5105 with ez start. My problem was the coil is different on the ez start model. Flywheels are the same but the key in the crankshaft was at 3 at tdc. I had to have the black coil. I also tried the red coils before i figured it out.

Thanks for the info do you know the part number for the black coil.

 

[turkeybob]

There were quite a few updates, I think latest part number was 181 143 213, 181 143 211 and 212 will work but there were some issues hence updates. Be careful of Chicom units, they say will fit but as far as I am aware none work on easy start models, I may be wrong of course, for the price it may be worth a try. For easy start they have some trick retard mechanism in the coil for low rpm starting,

 

[uziduzit9mm]

Thanks for all the info

 

[link]

So where is is the curare in your rearwiev mirror guy? He would know for sure.