Stihl MS180 Won't start after top end replacement

[Digital_Dad]

The brand new saw was run for about 5 mins with straight gas. It did damage the piston, rings and cylinder so I bought a rebuild kit from my Stihl dealer 1130 020 1208 and some Elring Dirko HT Sealant Red. I rebuilt the motor and put the saw back together. Now I have compression, I get spark, there is gas on the plug after trying to start it but it will not start?

 

[Dennisthemenace]

Air, fuel, spark and no leaks. These are the main things in a 2 stroke. Did you check numbers 3 and 4?

 

[Digital_Dad]

Air, fuel, spark and no leaks. These are the main things in a 2 stroke. Did you check numbers 3 and 4?

I have spark, I used a multimeter to check ohms between the coil wire and the coil housing and got 10.89 ohms. It has a good strong sparks when grounding the plug to the cylinder. My compression guage shows good compression equal to the new saw I bought. I do not have a pressure/vacuum pump.

 

[J D]

Timing, flooded, or (likely) an air leak

 

[Digital_Dad]

Timing, flooded, or (likely) an air leak

I thought timing too so I took it apart again and checked the flywheel was on right and in its notch, unfortunatly it was, the other thing I did was redo the spacing of the coil to the flywheel. That also led me to have to refix the coil end back on to the end of the coil wire again, this time it turned out even better than the last time. What a terrible design to have a sharp pointy piece of the wire puncturing the wire to make contact and a tighter than hell spring to lock it to the plug. It seems like you can't pull the coil wire off the plug without having to fix the piece on the end of the coil wire before putting it back together. I haven't got a chance to put it all back together yet to test it. If it doesn't work I will have to go buy a vacuum/preesure pump to test for leaks.

 

[Vintage Engine Repairs]

Empty the gas tank, pull it over at full throttle about 10 times. Then just put a teaspoon of fuel mix directly into the carburetor (just lift off the air filter) then full throttle again and try start it and see if it runs and dies. This eliminates spark (mostly) and compression. Then it leaves fuel and air.

 

[a. palmer jr.]

You need to twist the plug wire off the spark plug, not just pull on it.

 

[atpchas]

It seems like you can't pull the coil wire off the plug without having to fix the piece on the end of the coil wire before putting it back together.

See the video that Vintage Engine Repairs posted a while back on reattaching the contact to the the plug wire and snugging down the boot. He pointed out the very useful technique of wrapping some fine twine (I use monofilament fishing line) to keep the contact from coming loose - one of the many "tricks of the trade" I've picked up here and one of the best.

 

[Vintage Engine Repairs]

See the video that Vintage Engine Repairs posted a while back on reattaching the contact to the the plug wire and snugging down the boot. He pointed out the very useful technique of wrapping some fine twine (I use monofilament fishing line) to keep the contact from coming loose - one of the many "tricks of the trade" I've picked up here and one of the best.

Thanks, I use heat shrink to secure it down

 

[cookies]

set the coil gap with a business card or section of thin cardboard from the back of a spiral notepad. That plug may be bad under load, when flooded remove the plug and blow out the plug and cylinder with compressed air or pull it over 20 times and wait 10 minutes then retry starting without choke on high idle. Wd-40 is great for slipping ignition boots over terminals, it evaporates right after your done.

 

[atpchas]

Thanks, I use heat shrink to secure it down

I use LOTS of very fine filament and found it easier than the shrink wrap but that's what works for me. Point is your vid gives some really good ideas.

 

[Vintage Engine Repairs]

I use LOTS of very fine filament and found it easier than the shrink wrap but that's what works for me. Point is your vid gives some really good ideas.

That’s a really interesting idea, when you say filament, is that fishing line?

 

[stihltech]

Push the tang into the wire. Hold it in with pliers. Spray the plug boot with brake cleaner. Push the plug boot over the round end of the spring, small end first.
Push on as far as possible while holding the leg of the spring into the wire. When the pliers can no longer contact the leg of the spring, use your thumb to keep pressure on the backside of the boot and finish inserting. Straighten the round end in the plug boot to engage the plug terminal.
Sounds like a lot, but we are talking less than a minute. Definitely a "practice makes perfect" deal.
You get it down pat after the first 100.

 

[atpchas]

That’s a really interesting idea, when you say filament, is that fishing line?

That's it - something almost hairlike, maybe 2 pound test. Arthritis in my hands makes it more difficult to follow Stihltech's instructions, the tie down means I don't have to squeeze with my thumb or any other fingers. Added bonus, the the tang is far less likely to work its way out.

 

[Vintage Engine Repairs]

That's it - something almost hairlike, maybe 2 pound test. Arthritis in my hands makes it more difficult to follow Stihltech's instructions, the tie down means I don't have to squeeze with my thumb or any other fingers. Added bonus, the the tang is far less likely to work its way out.

Great idea, I’ll let you know how I go.

 

[HarleyT]

Sounds like a sheared flywheel key.

 

[stihltech]

If the plug hook on spring is piercing the outer covering to get to the inner plug wire at all, it will have a path for spark. Can't say I have seen one in 40+ years that caused a loss of spark from that.
Time to step back and start diagnosis from the beginning. We all have to do it at times.

 

[Okie]

You say:

Spark plug is wert with fuel.
Getting good spark.
Flywheel is timed correctly.

These are Symptoms of being flooded. A severely flooded saw is hard to get going.

Install another correct spark plug and hold throttle wide open and crank, several times

If no go

Take out the spark plug, crank over several times, let it set overnight, re-install spark plug and start over so as to try and not re-flood the saw. If a choke is applied later if it pops once remove all choke and hold wide open throttle.
Sometimes after a overhaul one will get flooded easy.