hyltaiwan

I guess you have some carbon stick on the exhaust valve stem, so your exhaust valve cuold not close completely.
That is also make your pushrod tend to fall out. Just guess, I saw similar condition before.

dale691

So where to now, I think it's full of oil and I don't think I'm going to get it started in this condition. It now 2 days old, do I pull it down and clean it or send the motor back?

bulldog319

Thanks for the info W8ye. That saved me $75 I was close to pulling the trigger on.

w8ye

My Feedback: (16)

Do you have compression now?

dale691

Yes I have compression now, but not firing. I think it is full of fuel and oil from all my attempts at trying to get it to go.

Anyone know if the washer on the spark plug is the same thickness as a normal glow plug washer?

hyltaiwan

Since your engine is new, I do'nt want to encourage you to disassemble the engine unless you have 100% confidence to that.
You may take off the exhaust manifold thenput a little thread in the exhaust port and let it pass through the valve stem and come out from the
other side. Hold both ends of the thread with your two hands and do the push-pull to clean the vavle stem. Take off the rockerarm cover, and
do the push and release to observe if valve moving freely. If it is too thick carbon there a sharp knife may be needed. I hope this will do some
help. Good luck to you.

w8ye

My Feedback: (16)

They are the same

Timbers

My Feedback: (3)

I got the engine running tonight!!!!

I sent it back to Horizon, and got it back last week. They sent it with a new Satio spark plug in it. I noticed that the spark plug element was lower in the body of the plug than the one that came with my engine. The electrode is flush with the bottom of the plug. The one that came with the engine, the electrode is sticking out of the bottom of the plug. Now the L shaped part of the plug, that catches the spark from the electrode on the NEW plug is bent downwards, to maintain the gap in the plug. The plug that came with the engine, the L shaped piece is actually a perfect 90 degrees.

Iwas able to get my engine up to 9600RPM with a 15x6 prop tonight with no missing at the top end. The sucker PULLS big time.

After 10 minutes of flying the engine started to miss a little bit again, so I freaked out and landed. I don't know, maybe I had it too rich, maybe the level in the tank affected it, maybe it overheated? Not sure. All I know is the engine is running 100% better now with this new plug.

I wasn't able to get above 8400RPM with a 15x6 APC before this new plug.

I'm much happier.I hope Ican get it tuned to perfection now.

...Tim

w8ye

My Feedback: (16)

I would venture to say that the left hand plug is a homemade attempt at a colder heat range? No!

I have four Saito plugs and three look like the one on the right. One looks like the one on the left. And appears to be a production anomaly. Just poor production tolerances?

I also have a Rimfire and it also looks like the one on the right

dale691

Good news on y front. I have got it running again, it seems the plug was so oiled up from all the attempts to start it while the rocker arm wasn't functioning. 

w8ye

My Feedback: (16)

Like a previous post said, the valve was probably stuck for a moment and let the pushrod fall out?

dale691

I would say that was the case. Just wish I had picked that up sooner and then I wouldn't have made such a mess of the plug, and caused my self a lot longer cleaning my mess up!

hyltaiwan

If your FG20 wouldn't reach 9500rpm by 15x6, or 8700rpm by 15x8 .  Then I guess that you have air in the pump, see my previous post.

RickVB

My Feedback: (24)

Wow, how depressing. Shoulda read this thread before buying one myself, especially since I want to use it as a replacement for my recalcitrant RCS 140 that I finally got tired of fighting with in my Cub. i may have traded one problem for another... but my hardheadedness forces me to forge on and try anyway.

The reason I started looking here about this engine was to see what others have been doing about mounting this thing. I haven't seen any great ideas so far. What the heck was Saito thinking hanging that big hunk of carb on the side of the back right where it would interfere with engine mounts? They could have oriented it towards the middle of the back with an offset intake manifold like their glow engine carbs are. What the heck? The result for me is that I must also replace the perfectly otherwise usable Dubro metal vibration damping mount that the RCS 140 is currently on.

If anyone else has come up with a better idea than the Saito mount, please let us see it.

Timbers

My Feedback: (3)

We had a great weekend at our field, and I got my FG-20 running great. It was pulling and sounding awesome. Bad news is another problem has surfaced now. I landed after the 3rd flight and found I had zero compression. Iwas like, crap I burned the piston up? Well Idon't think that is the case. IthinkI have a stuck valve, or a valve that isn't seating completely. I can start the engine and after awhile it starts running great again. Tons of compression. Now its at the point where it has zero compression.

I took the valve covers off and it doesn't seem like the valves are stuck, but they have to be. Weird thing is Iwill adjust the exhaust valve, and after a flight it will come down and the rocker arm will be tight. So I loosen it up and it runs fine again, but tightens back up.

I don't know what to do now? Send it back to Horizon AGAIN, this time tell them the valves are sticking?????

Sucks. I mean Ilike to tinker, but this might be getting to be a bit much. I got the engine running nice, which Iam really happy about. But now this?

w8ye

My Feedback: (16)

One of mine did this and it was the rocker arm pivot pin for the exhaust valve. I thought I was never going to get the pivot pin out of the rocker arm. It was full of rust in the pivot area. The engine was NIB the day before. The pin had galled and frozen the rocker arm.

I cleaned the galled area off the pin and reassembled with grease on the pin. I ran it for a couple more hours and it didn't freeze up.

Timbers

My Feedback: (3)

How did you know the rocker arm wasn't moving freely? Mine move the valves around, its not like they are sticking it seems? I'm wondering if I need to pop the head off the engine and clean the valves and valve seats? I'll check the rocker arms tomorrow to make sure they are moving correctly.

...Tim

w8ye

My Feedback: (16)

The first indication was that the pushrod jumped out from under its socket in the rocker arm. when I replaced the pushrod where it belonged and forced the rocker arm onto the pushrod, the valve came up on its own. I could then push the valve down and it would return to the rocker arm which was stationary and stiff.

There was plenty of oil in there and rust too. I cleaned it all out and adjusted the valves down to .002" which were greater than .010".

Timbers

My Feedback: (3)

Did you take your engine apart? I'm thinking about doing this tomorrow. I bet there is a ton of carbon build up. Maybe I am running it too rich?

w8ye

My Feedback: (16)

No don't take the engine apart. Just take the exhaust valve cover off and check the freedom of the valve itself. Put some oil around the valve stem


I don't use any of that fancy synthetic oil in mine. The synthetic oil makes the carbon hard.
I use Pennzoil Two stroke Aircooled. The carbon stays real soft. 20:1

cde

Ditto, I was ready to jump in with both feet on thisengine but sounds like Saito has some work to do...I'm done being a guinea pig for manufactures.

w8ye

My Feedback: (16)

I have two of the FG-20 engines. I like them very well. I just ran a new in box one on the test stand last week end.

Started right up. Treat the tank position and the needle operation like it was a glow engine and there will be no problems.

I used a bubbleless clunk and Dubro neoprene tubing for the clunk line in the tank. Used a Dubro Gas stopper. Used the yellow Tygon line from the tank to the engine. Three Tygon tubes. One from clunk to carb. One vent. One fill line that is kept plugged except for filling.

Engine ran perfect for 8 tanks of fuel whereby it quit. Found that the exhaust rocker arm was frozen up with rust. The rust was the result of something Saito did for this engine was only run this one day. After eventual removal and dressing up the pin and adding grease to the pivot pin, the engine was up and running again with no problem

I have 28 Saito engines. Some were old ones I rebuilt and some were new when purchased. I didn't find the two Saito FG-20 engines any different than any other Saito engine.

The biggest place where I found that Saito dropped the ball is the manual. Though it is even a poor excuse for the FG36, about the only part of it that applies the the FG-20 is the name on the cover. I think my grand daughter could have done a better job if you gave her an old manual for another engine to copy. I don't normally read the manuals anyway so this matters little to me.

Upon removing the engine from the box, I first noticed the crankcase vent only had a 1/16" hole in it. I removed the back plate and ran a drill through the vent from the inside out. The vent was almost closed off from metal pushed over the hole by the cut-off tool when it was made.

I now have two great sport gas engines to go along with my two Saito 125's

Scooterpilot

My Feedback: (5)

W8YE,

Thanks for the update.

rc4j

My Feedback: (103)

I'll second that!

rmalko

I was at the field today to try out my FG 20 set up like it is a glow engine and found I still had the same problems as before. At idle it seems to shake a lot and vibrate the plane like crazy. The high end still sputters and can't get past 7400 rpm or so. I think I might send this one to Horizon and have them look at it. I thought I would give this setup a chance since there have been a few people here who say their fg 20 is running well.