O.S 91 four stroke starting problems
02-21-2010 | 06:49 PM
#1
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From: St. Clair Shores, MI
O.S 91 four stroke starting problems
Alright I was hoping for some advice. I am having a very difficult time starting my O.S 91 Four Stroke. I purchased a Great Planes Piper Cub float plane from the classifieds on this site late last fall. When I first got it home I had a very difficult time getting it to start although after some work it always ran. It was even difficult to start after it had warmed up. I went out to the garage today to pull the floats and get it ready for the field and thought Iwould run it for a few minutes. I started by checking my valve clearences, fueling, checking throttle and linkage along with all control surfaces, primed engine a few turns, then tried to start. No go. Pulled glow plug and it is wet and glows. Re-installed glow plug and attempted it again. No go. I thought because it was cold Ishould attempt to richen the mixture. Iwent from two turns out to two and a half turns then to three. Still the engine would not fire. I ran the throttle at every position possible and it would still not run. What am Idoing wrong. Ihave seen these engines just fire right up with no effort. Please help guide me in the right direction.
02-21-2010 | 08:26 PM
#3
RE: O.S 91 four stroke starting problems
I would agree with Gary. Whenever I first start my engines for winter time flying (frozen lakes) in Late December and January, i always use some lighter fluid (for Zippo-type lighters). I either squirt it in the carb, or in the glow plug hole. See if it will pop on this stuff, and then try the Type F.
good Luck,
Curtis
good Luck,
Curtis
02-21-2010 | 08:26 PM
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From: Quinlan,
TX
RE: O.S 91 four stroke starting problems
Sometimes a four stroke doesn't get enough prime by pulling the prop through. Put your finger over the exhaust outlet with the glow battery connected. Spin the engine with the starter until the engine fires. Watch out for the prop!! I've managed to get my forearm in the prop a time or two when the plane moved while starting. I highly suggest using a helper to either plug the exhaust or spin the starter. After the first start it will usually start by just applying the starter. Good luck.
Paul
Paul
02-21-2010 | 09:15 PM
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From: St. Clair Shores, MI
RE: O.S 91 four stroke starting problems
Thanks I will try both the zippo fluid and a new f plug. Iwill keep you guys posted. Thanks again.
02-21-2010 | 09:54 PM
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From: Sterling , CO
RE: O.S 91 four stroke starting problems
What compression do you have. It should be real hard to turn over, and they will not fire if you try to start in reverse with Elec. starter,not saying you are trying it back wards but things happen.
02-21-2010 | 10:18 PM
#7
My Feedback: (-1)
RE: O.S 91 four stroke starting problems
A few drops of lighter fluid and the new plug is a big help. Even here when it gets into the 30s or high 20s mine are harder to start. That's when I quit using my clip on glow driver and go to my power panel with the juice turned up. I have a few of the .91s and for some reason they are very cold blooded?? Sometimes when it goes into the 20s {high 20s} I roll the engine over with my starter and have someone put there finger over the muffler hole too, sort of a close and open thing until it starts. I leave the driver on the plug and run my engine up to about 4000rpm for about a half minute or so then it's good to go.
02-22-2010 | 08:22 AM
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From: ChelmsfordEssex, UNITED KINGDOM
RE: O.S 91 four stroke starting problems
ORIGINAL: Gray Beard
A few drops of lighter fluid and the new plug is a big help. Even here when it gets into the 30s or high 20s mine are harder to start. That's when I quit using my clip on glow driver and go to my power panel with the juice turned up. I have a few of the .91s and for some reason they are very cold blooded?? Sometimes when it goes into the 20s {high 20s} I roll the engine over with my starter and have someone put there finger over the muffler hole too, sort of a close and open thing until it starts. I leave the driver on the plug and run my engine up to about 4000rpm for about a half minute or so then it's good to go.
A few drops of lighter fluid and the new plug is a big help. Even here when it gets into the 30s or high 20s mine are harder to start. That's when I quit using my clip on glow driver and go to my power panel with the juice turned up. I have a few of the .91s and for some reason they are very cold blooded?? Sometimes when it goes into the 20s {high 20s} I roll the engine over with my starter and have someone put there finger over the muffler hole too, sort of a close and open thing until it starts. I leave the driver on the plug and run my engine up to about 4000rpm for about a half minute or so then it's good to go.
10% nitro, 18% ML70 synthetic.
02-22-2010 | 11:06 AM
#9
RE: O.S 91 four stroke starting problems
Every 4-stroke I have ever owned likes to start wet, especially when cold. That's in the 20's-30's that we get at the field here. Obviously it is much colder there in Michigan so they probably need to be really wet. Never needed to try the lighter fluid myself but I hear it does work.
I wll have to try that.
02-23-2010 | 07:55 PM
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From: VIRGINIA BEACH,
VA
RE: O.S 91 four stroke starting problems
COLD wEATHER STARTS??
"Convince" the engine that it is summer! When you arrive at your flying site "stick" the head of the engine into the exhaust of your car/truck for a few minutes - then use your normal starting process.
Tony
"Convince" the engine that it is summer! When you arrive at your flying site "stick" the head of the engine into the exhaust of your car/truck for a few minutes - then use your normal starting process.
Tony
ORIGINAL: Dante421
Alright I was hoping for some advice. I am having a very difficult time starting my O.S 91 Four Stroke. I purchased a Great Planes Piper Cub float plane from the classifieds on this site late last fall. When I first got it home I had a very difficult time getting it to start although after some work it always ran. It was even difficult to start after it had warmed up. I went out to the garage today to pull the floats and get it ready for the field and thought I would run it for a few minutes. I started by checking my valve clearences, fueling, checking throttle and linkage along with all control surfaces, primed engine a few turns, then tried to start. No go. Pulled glow plug and it is wet and glows. Re-installed glow plug and attempted it again. No go. I thought because it was cold I should attempt to richen the mixture. I went from two turns out to two and a half turns then to three. Still the engine would not fire. I ran the throttle at every position possible and it would still not run. What am I doing wrong. I have seen these engines just fire right up with no effort. Please help guide me in the right direction.
Alright I was hoping for some advice. I am having a very difficult time starting my O.S 91 Four Stroke. I purchased a Great Planes Piper Cub float plane from the classifieds on this site late last fall. When I first got it home I had a very difficult time getting it to start although after some work it always ran. It was even difficult to start after it had warmed up. I went out to the garage today to pull the floats and get it ready for the field and thought I would run it for a few minutes. I started by checking my valve clearences, fueling, checking throttle and linkage along with all control surfaces, primed engine a few turns, then tried to start. No go. Pulled glow plug and it is wet and glows. Re-installed glow plug and attempted it again. No go. I thought because it was cold I should attempt to richen the mixture. I went from two turns out to two and a half turns then to three. Still the engine would not fire. I ran the throttle at every position possible and it would still not run. What am I doing wrong. I have seen these engines just fire right up with no effort. Please help guide me in the right direction.
02-23-2010 | 08:06 PM
#13
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RE: O.S 91 four stroke starting problems
ORIGINAL: tgeorge
COLD wEATHER STARTS??
''Convince'' the engine that it is summer! When you arrive at your flying site ''stick'' the head of the engine into the exhaust of your car/truck for a few minutes - then use your normal starting process.
Tony
COLD wEATHER STARTS??
''Convince'' the engine that it is summer! When you arrive at your flying site ''stick'' the head of the engine into the exhaust of your car/truck for a few minutes - then use your normal starting process.
Tony
ORIGINAL: Dante421
Alright I was hoping for some advice. I am having a very difficult time starting my O.S 91 Four Stroke. I purchased a Great Planes Piper Cub float plane from the classifieds on this site late last fall. When I first got it home I had a very difficult time getting it to start although after some work it always ran. It was even difficult to start after it had warmed up. I went out to the garage today to pull the floats and get it ready for the field and thought I would run it for a few minutes. I started by checking my valve clearences, fueling, checking throttle and linkage along with all control surfaces, primed engine a few turns, then tried to start. No go. Pulled glow plug and it is wet and glows. Re-installed glow plug and attempted it again. No go. I thought because it was cold I should attempt to richen the mixture. I went from two turns out to two and a half turns then to three. Still the engine would not fire. I ran the throttle at every position possible and it would still not run. What am I doing wrong. I have seen these engines just fire right up with no effort. Please help guide me in the right direction.
Alright I was hoping for some advice. I am having a very difficult time starting my O.S 91 Four Stroke. I purchased a Great Planes Piper Cub float plane from the classifieds on this site late last fall. When I first got it home I had a very difficult time getting it to start although after some work it always ran. It was even difficult to start after it had warmed up. I went out to the garage today to pull the floats and get it ready for the field and thought I would run it for a few minutes. I started by checking my valve clearences, fueling, checking throttle and linkage along with all control surfaces, primed engine a few turns, then tried to start. No go. Pulled glow plug and it is wet and glows. Re-installed glow plug and attempted it again. No go. I thought because it was cold I should attempt to richen the mixture. I went from two turns out to two and a half turns then to three. Still the engine would not fire. I ran the throttle at every position possible and it would still not run. What am I doing wrong. I have seen these engines just fire right up with no effort. Please help guide me in the right direction.
i use plain old charcol lighter fluid and it makes a big difference, i put some in an old spray applicator bottle and squirt some in the engine to get her going.
some of my two strokes are a real pain to get going but the 4 strokes are much worst. i have to turn my magnum .52 over for a while before it pops, it doesnt help that i use a nicd powered starter and nimh powered glow ignitor
02-23-2010 | 08:49 PM
#14
RE: O.S 91 four stroke starting problems
Lighter fluid is the best. My planes sit for about 2 months before I fire them up at the end of December when the lakes have safely frozen and they become my (nearly) unlimited airstrip. By then the weather is freakin cold (0F) and my tuning settings have changed a fair bit and the oil has congealed in the engine. The lighter fluid cuts the oil and really helps get the engine firing. On my inverted 4S, just a squirt down the carb is enough, but if that is not possible, then I pull the plug and spit it in the crankcase.
I haven't tried to warm the engine in the exhaust, but the lighter fluid works pretty well and making sure your glow driver is well charged helps.
Good Luck,
C
I haven't tried to warm the engine in the exhaust, but the lighter fluid works pretty well and making sure your glow driver is well charged helps.
Good Luck,
C
02-23-2010 | 09:54 PM
#16
Senior Member
RE: O.S 91 four stroke starting problems
And I was thinking Iwas the only one having troubles. My OS91Surpassarossa starts terrible cold. Iattributed it to weak compression.
02-23-2010 | 11:39 PM
#17
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RE: O.S 91 four stroke starting problems
ORIGINAL: jeffie8696
And I was thinking I was the only one having troubles. My OS91Surpassarossa starts terrible cold. I attributed it to weak compression.
And I was thinking I was the only one having troubles. My OS91Surpassarossa starts terrible cold. I attributed it to weak compression.
02-24-2010 | 12:07 AM
#18
Senior Member
RE: O.S 91 four stroke starting problems
Yea Ihave tried the extra rich thing , even had fuel blowing out the exhaust to no avail. It just decides to fire when it wants to
Ialways get it eventually. Heat gun would probably help.
Ialways get it eventually. Heat gun would probably help.
02-25-2010 | 11:30 AM
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From: ChelmsfordEssex, UNITED KINGDOM
RE: O.S 91 four stroke starting problems
ORIGINAL: jeffie8696
Yea Ihave tried the extra rich thing , even had fuel blowing out the exhaust to no avail. It just decides to fire when it wants to Ialways get it eventually. Heat gun would probably help.
Yea Ihave tried the extra rich thing , even had fuel blowing out the exhaust to no avail. It just decides to fire when it wants to
Ialways get it eventually. Heat gun would probably help.
02-25-2010 | 11:37 AM
#20
RE: O.S 91 four stroke starting problems
Hi!
Most of the time newbies have trouble starting their engines is because they don't use enough glow power!
Use an automatic glow driver powered by a 12V 10-12A motorcycle battery!
Do not rely on small NiCad 1,2v glow drivers.
The glow plug should glow yellow white and not dull red or dull orange!
Use an electric starter!
Use a 14x6 or 15x4-15x6 APC prop.
Most of the time newbies have trouble starting their engines is because they don't use enough glow power!
Use an automatic glow driver powered by a 12V 10-12A motorcycle battery!
Do not rely on small NiCad 1,2v glow drivers.
The glow plug should glow yellow white and not dull red or dull orange!
Use an electric starter!
Use a 14x6 or 15x4-15x6 APC prop.
