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I pulled and pulled and pulled at least 30 times but could not get this trimmer started. I did all the necessary stuff (prime, crank in off position a few times, flip switch up, crank again) but it WOULD not start.
Any suggestions?

Try it again. If no start, pull the plug to see if it is wet with gas. If it is then check for spark. Is your fuel stale? Air filter clean?

possum said:

Try it again. If no start, pull the plug to see if it is wet with gas. If it is then check for spark. Is your fuel stale? Air filter clean?

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I'll check plug tomorrow. Fuel is good. I took the air filter out and it was a little rough looking but it still wouldn't start with filter out.
Thanks

Test the coil, with a meter.

EngineMan said:

Test the coil, with a meter.

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Where's the coil?

possum said:

check for spark. Is your fuel stale? Air filter clean?

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I put a new plug and air filter in. Cranked it and still won't turn over. Fuel is the same I've been using all season. I'll crank it and look for spark tomorrow and check back in here.

So I think it's flooded. The primer bulb is full. I got home from work, cranked it and it fired right up. I didn't prime it or anything.
Pic here

My stihl has starting problems when I prime it. floods it. Now when its hot thats the only time ill prime it. Try just choke starting it

exotion said:

My stihl has starting problems when I prime it. floods it. Now when its hot thats the only time ill prime it. Try just choke starting it

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Clean the spark arrestor screen.

Moe green said:

Clean the spark arrestor screen.

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Removed it completely, the trick is to prime when hot outside, choke when not

EngineMan said:

Test the coil, with a meter.

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G'day all.

How is the test done?

With a regular multimeter I guess, and on volts?

I have FS45 that is giving me hell.

It came in my shop running at 1/5th the power.
- Tried adjusting the high and low, but no good.
- Put a new carby gasket kit in and it started running well.
- Customer came back a few days later. Machine was doing the same 1/5th power thing again.
- I pulled down the carby and checked everything was OK, but still same prob.
- Exhaust is clear. Tried to run it for a few seconds without just to make sure, but still 1/5th power.
- I tried three plugs.
- It has good wrist snapping compression
- Fresh fuel
- Good fuel lines

Next I bought a new carby of ebay.

Still running at 1/5th power.

All I can think of is a weak coil maybe?

Any ideas?

Cheers.
Aussie.

Aussierod,

The ignition module of most, if not all, stihl equipment is considered to be disposable and even in their own Stihl dealers there is no standardized way of measuring the AC volts as a trouble shooting tool. That being said it could be that ignition module. If I had that FS 45 in my shop I would run the gamut of vacuum/pressure tests on the crankcase and def check out the muffler/spark arrestor.

Buzgod said:

Aussierod,
def check out the muffler/spark arrestor.

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Dang nabit, I've been used to the old style square mesh screen.

I wiped all the grease away from the FS45 exhaust outlet and had a closer look.

BINGO!! :wink:

OK, so this model has a screw in insert with a round mess inside that can be taken out with a 15mm socket.

Thing runs like new now. Customer got a new carby in the ordeal as well.

Ow well, live and learn.

Thanks mate :thumbsup:

I am completely flumoxed (Olde English word). My Stihl FS45 suddenly stopped whilst in use about 6 weeks ago and would not restart. So I started checking and found no spark. I replaced the magneto coil, ON/OFF switch (but that is OK) and spark plug and now I get a spark, but still no start. My next action was to buy and fit a new carburettor in case the small fiddly diaphragms had perished or split and at the same time cleaned out the fuel tank and filter ( but already quite clean) and removed and cleaned the silencer/muffler which here in the UK has no spark arrester. Compression is good and there are no signs of any crankcase leakage. As far as I can tell, the magneto/spark timing is OK as the flywheel magnets are centred on the magneto as the piston comes to top dead centre. What's left? Do I just junk it and put it down to experience having more or less completely rebuilt it ?

Any ideas anybody? Grateful for any insight on this intractable problem.