FE-350 Top End

datcat · 11-25-2009, 05:21 PM

Just got my service manual for my 1200 Util Cart. Been waiting to see the specs before I started quizzing the experts. Engine's got 2000 hrs on it, doesn't smoke or knock but is quite tempermental and cold natured. I can deal with it but the women folks that will be driving it will no doubt be less forgiving. Anyway, manual calls for 71 #'s compression as minimum...read with an automatic release gage...I have a standard gage and I'm getting about 62 #'s after about 3 compression strokes (very consistantly repeating). Am I truly too low or is this a borderline condition. My experience has been with 2 strokes and the first sign would be the hard to start issues so this was my first clue. The other couple of conditions I need to start figuring out before bolts start to fly seem to be carb/gov related. On flat ground or going downhill you can't find a constant position for the throttle. It wants to hunt like the governor is over compensating. Uphill or under a load...no issues. I'm was a refinery mechanic/machinist by trade and I dealt with other governor systems (hydraulic/electronic) and I know misadjustment and slop in the system will cause this. Any other thoughts? I've got the manual now and will start from scratch and go through the adjustment sequence. The final condition I've noticed is a backfire when I get off the gas after the engine has warmed up. While searching the forum for something about this I came across similar issues on pedal start units where there's no fire when off the pedal and the butterfly valve not being fully closed causing a continuous flood to the cylinder...this is a key start engine that fires all the time so I didn't know if this would still be the case.

datcat · 11-25-2009, 08:59 PM

Maybe too many questions at once??

Let's just start with the 62 #'s of compression...low enough to dive into a top end overhaul?

invalidsession · 11-26-2009, 01:21 AM

Quote:

Originally Posted by datcat

Maybe too many questions at once??

Let's just start with the 62 #'s of compression...low enough to dive into a top end overhaul?

1st thing I would do Dat is squirt some oil down the spark plug hole and re-do the compression test. A significant jump in psi would suggest a bore, piston or rings problem whereas no rise would lead me to the valves. If the latter, first check clearances of the valves and if that doesn't do the trick then "off with its head" for a more thorough check on the valve seating, if the former then it's time for a more detailed analysis of the bore etc.
Hope that helps.

Chris.

lockman1 · 11-26-2009, 09:10 AM

I'm just going to throw this out there...

I was looking at my FE350 manual, and saw that the key start FE350's have an:
Automatic Compression Release Valve (ACR)

BUT... I can't find where, or what it is, anywhere in my manuals
(I only have experience with pedal start carts... which don't have an ACR, so this is new to me!)

Could it be possible that the ACR is not functioning correctly???

Just a thought... (again... no experience with the ACR, but it sounded like a good place to start!)

datcat · 11-26-2009, 10:57 AM

Quote:

Originally Posted by invalidsession

1st thing I would do Dat is squirt some oil down the spark plug hole and re-do the compression test. A significant jump in psi would suggest a bore, piston or rings problem whereas no rise would lead me to the valves. If the latter, first check clearances of the valves and if that doesn't do the trick then "off with its head" for a more thorough check on the valve seating, if the former then it's time for a more detailed analysis of the bore etc.
Hope that helps.

Chris.

Thanks Chris...valve clearance shouldn't be the case as the 350/400 have hydraulic lifters and don't require adjusting but I'll give the oil test a shot.

invalidsession · 11-26-2009, 11:05 AM

Hmmm, that's interesting Lockman. I know squat about the key start version either but the page you showed suggests an "ACR" (automatic compression release) of approx 71psi untill 500+ rpms have been attained. Pretty close to what datcat is reading at cranking speed which would suggest a normal condition in his case.
Perhaps someone could chip in with a suggestion to temporarily disable the ACR to verify correct compression and operation of this device ?
An Old single cylinder 500 Yamaha is the last time I encountered a compression release for starting, it was a simple cable operated valve on the cylinder head and easily disabled. I would also be interested to know why it has such a function. Other than allowing the motor to spin up with less strain on the battery, starter motor etc what purpose does it serve ? Pedal start carts are subject to many more stop / start cycles and suffer few problems. With the aforementioned Yamaha it was simply to aid kick starting.

Chris

11-25-2009, 05:21 PM	#1
datcat Not Yet Wild Join Date: Aug 2009 Location: Beaumont, TX Posts: 14	FE-350 Top End Just got my service manual for my 1200 Util Cart. Been waiting to see the specs before I started quizzing the experts. Engine's got 2000 hrs on it, doesn't smoke or knock but is quite tempermental and cold natured. I can deal with it but the women folks that will be driving it will no doubt be less forgiving. Anyway, manual calls for 71 #'s compression as minimum...read with an automatic release gage...I have a standard gage and I'm getting about 62 #'s after about 3 compression strokes (very consistantly repeating). Am I truly too low or is this a borderline condition. My experience has been with 2 strokes and the first sign would be the hard to start issues so this was my first clue. The other couple of conditions I need to start figuring out before bolts start to fly seem to be carb/gov related. On flat ground or going downhill you can't find a constant position for the throttle. It wants to hunt like the governor is over compensating. Uphill or under a load...no issues. I'm was a refinery mechanic/machinist by trade and I dealt with other governor systems (hydraulic/electronic) and I know misadjustment and slop in the system will cause this. Any other thoughts? I've got the manual now and will start from scratch and go through the adjustment sequence. The final condition I've noticed is a backfire when I get off the gas after the engine has warmed up. While searching the forum for something about this I came across similar issues on pedal start units where there's no fire when off the pedal and the butterfly valve not being fully closed causing a continuous flood to the cylinder...this is a key start engine that fires all the time so I didn't know if this would still be the case.

11-25-2009, 08:59 PM	#2
datcat Not Yet Wild Join Date: Aug 2009 Location: Beaumont, TX Posts: 14	Re: FE-350 Top End Maybe too many questions at once?? Let's just start with the 62 #'s of compression...low enough to dive into a top end overhaul?

11-26-2009, 11:05 AM	#6
invalidsession Gone Wild Join Date: Aug 2009 Location: Eldon Missouri Posts: 977	Re: FE-350 Top End Hmmm, that's interesting Lockman. I know squat about the key start version either but the page you showed suggests an "ACR" (automatic compression release) of approx 71psi untill 500+ rpms have been attained. Pretty close to what datcat is reading at cranking speed which would suggest a normal condition in his case. Perhaps someone could chip in with a suggestion to temporarily disable the ACR to verify correct compression and operation of this device ? An Old single cylinder 500 Yamaha is the last time I encountered a compression release for starting, it was a simple cable operated valve on the cylinder head and easily disabled. I would also be interested to know why it has such a function. Other than allowing the motor to spin up with less strain on the battery, starter motor etc what purpose does it serve ? Pedal start carts are subject to many more stop / start cycles and suffer few problems. With the aforementioned Yamaha it was simply to aid kick starting. Chris

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