Ryobi S430 4cycle trimmer won't fire?

[jwales]

This is a 4 cycle trimmer, straight shaft. Checked for spark and that is strong. Adjusted the valves (they were not to loose) to spec. fuel lines and carb have been cleaned. I can't even get it to fire with a shot of starting fluid in the carb. I have not checked actual; compression but it feels good when pulling it over. Any ideas on what to check next??
Thnaks.

[bgsengine]

New Plug, Spark Arrestor (muffler restrictions) , Compression check - in that order would be what I'd check

Oh yeah - also check flywheel key/timing (valve timing too, perhaps?)

[KE4AVB]

File 13 it...Not worth the trouble...

Most likely if like the ones I have seen in the last two yrs the PNC is bad from lack of proper oiling. Can only be short blocked. And if it is the timing belt you will need a hydraulic press to disassemble the crankshaft and that is nearly a complete dismantling of the trimmer engine.

[rogerf]

Hallo Folks,

Sorry for the dumb question, but what's PNC? I looked for PNC on Google and came up with a financial institution and a retirement fund

Somehow I don't think there's a retirement fund for 4 cycle trimmers!

Looking forward to find out what the dreaded PNC failure is.

Cheers, Roger.

[jwales]

The plug is good, strong spark. I will check the spark arrester/muffler....completely over looked that, I guess thinking it was an issue with 2 cycles instead. Do you know what the compression range should be??

I also do not know what PNC is, so am also interested. The timing belt is intact. The oil was awful dirty, so I did change it.

I just can't believe I could not get it to fire with a shot of starting fluid. My neighbor said to toss it, he is buying a new one next spring. It has me curious so I will play a little more (but not much) with it before tossing.

Thanks

[bgsengine]

The plug is good, strong spark.

How do you know the plug will fire under compression? New Plug is not the same thing as Good plug - try another one that fits (even if it isn't correct as long as it has same thread and reach)

I will check the spark arrester/muffler....completely over looked that, I guess thinking it was an issue with 2 cycles instead. Do you know what the compression range should be??

Minimum 65 PSI I would say considering it is 4-stroke

I also do not know what PNC is, so am also interested.

an acronym referring to Piston and Cylinder .. Us old-school techs refer to it as the "Jug Kit"

The timing belt is intact.

Yes but could it have jumped time? - with cover off to see the flywheel magnets passing coil, observe valve action (and/or with a pencil in the spark plug hole to see TDC) and see if you get valve overlap at the right piston position (and the magnets should have *just* passed the coil legs to trigger spark at TDC) then you can assume timing is pretty much where it should be

The oil was awful dirty, so I did change it.

I just can't believe I could not get it to fire with a shot of starting fluid. My neighbor said to toss it, he is buying a new one next spring. It has me curious so I will play a little more (but not much) with it before tossing.

Thanks

Yeah they are usually not worth putting a whole lot into which is why I almost never see them for service - costs more to fix them than to replace them.

[Fulltilt]

Any ideas on what to check next??

I would check to see if ya got enuff room in the trash can for it.

Or

As mentioned, check the flywheel for sheared key. Just because you have a strong spark, it could be at the wrong time.

[KE4AVB]

I will check the spark arrester/muffler....completely over looked that, I guess thinking it was an issue with 2 cycles instead. Do you know what the compression range should be??

Minimum 65 PSI I would say considering it is 4-stroke

Actually on these it is 90-125 PSI.

Readings in psi and possible causes
<20 (1.4 Bar)
Most likely a stuck valve or too tight of a valve lash, provided the starter rope pulls with normal effort.

20-90 (1.4 - 3 Bar)
Valve seat damage or piston ring and/or cylinder wear.

90 - 125 (6.2 - 8.6 Bar)
Normal readings

>125 (>8.6 Bar)
Excessive valve lash, a partial hydraulic lock, a bad cam or a bad automatic compression relief.

[rogerf]

Hallo Folks,

Thanks for the translation of 'PNC' Now the reply makes a lot of sense.

A 'jug' has a more common meaning here. It refers to an older type of electric kettle or more generally any electric kettle. Any respectable workshop has one We use them a lot for making tea or coffee.

I don't recall ever seeing an electric kettle on my visits to the US. Maybe your 110 volt system makes them too slow. They're usually at least 2kW so they heat to boiling quickly and use a standard 10A electrical outlet on our 230v system. With the 110v system in the US and Canada they'd be a lot slower if using a standard electrical outlet.

Cheers, Roger.

[bgsengine]

Hallo Folks,

Thanks for the translation of 'PNC' Now the reply makes a lot of sense.

A 'jug' has a more common meaning here. It refers to an older type of electric kettle or more generally any electric kettle. Any respectable workshop has one We use them a lot for making tea or coffee.

I don't recall ever seeing an electric kettle on my visits to the US. Maybe your 110 volt system makes them too slow. They're usually at least 2kW so they heat to boiling quickly and use a standard 10A electrical outlet on our 230v system. With the 110v system in the US and Canada they'd be a lot slower if using a standard electrical outlet.

Cheers, Roger.

LOL - here a "Jug" was actually something you would carry water in (Water Jug) so I guess the cylinder shape at the time *(when held spark plug side down) is where the name came from. It sounds like your canadian jug is our electric hot plate or coffee maker - most of the older style ones are long since obsoleted but some are still in use (percolators) - heck a long time ago by removing the heat sensor (to limit temperature) I made a home made electric hot plate out of an old electric iron.. haha

I guess the term "Jug" was just easier slang to pronounce and it might be just regional to this area I dunno, but around here someone talking about "Throw a Jug Kit At It" was understood to be referring to the cylinder and piston assembly...