Four Stroke install help
08-27-2008 | 08:01 PM
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From: Ruston,
LA
Four Stroke install help
I have a thunder tiger 91 four stroke and I need help with how to install the fuel and vent lines. I am only use to installing 2 strokes where there are 4 line connectors on the engine, and there are only 3 on my four stroke.
Anyone have a diagram or willing to explain how to set it up?
Thanks
Anyone have a diagram or willing to explain how to set it up?
Thanks
08-27-2008 | 08:20 PM
#2
RE: Four Stroke install help
I'm not sure what you mean by 4 lines on a 2-stroke. The engine only gets lines connected in two places generally: the carb/fuel inlet and the exhaust pressure nipple. The 4-stroke should be no different.
You can plumb a 3'rd line for filling and draining the tank but that has nothing to do with the engine.
Do you have the instructions that came with your 4-stroke?
You can plumb a 3'rd line for filling and draining the tank but that has nothing to do with the engine.
Do you have the instructions that came with your 4-stroke?
08-27-2008 | 08:36 PM
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From: Ruston,
LA
RE: Four Stroke install help
I meant there are normally 2 lines (fuel, vent) coming from the fuel tank that connect to the engine. On my other 2 stroke, besides those two lines connected to the engine, there are 2 more that i connect to each other.
08-27-2008 | 08:49 PM
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From: MCALISTERVILLE,
PA
RE: Four Stroke install help
I have a .91 thunder tiger 4-stroke and it has 3 lines....one from tank to carb nipple,one from tank to muffler nipple to pressurize the tank...and has one line coming out the bottom of the engines crankcase nipple that is simply a vent that expels excess oil that I hook a tube to and run out the bottom of my plane.
If your engine is the same setup as mine....I hope this helps...if not,explain more.
If your engine is the same setup as mine....I hope this helps...if not,explain more.
08-27-2008 | 08:54 PM
#5
RCU Forum Manager/Admin
My Feedback: (9)
RE: Four Stroke install help
I was just looking through the manual for that engine and Jester is right. There should be only 3 nipples on the engine. One on the muffler for tank pressure, one on the carburetor for fuel intake, and one on the bottom of the crankcase for your crankcase vent line. Where is the 4th line that you are referring to??
Ken
Ken
08-27-2008 | 08:56 PM
#6
RE: Four Stroke install help
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
Bill, AMA 4720
WACO Brotherhood #1
08-27-2008 | 09:24 PM
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From: Ruston,
LA
RE: Four Stroke install help
That answers exactly what I wanted to know. Thanks a lot
I am use to having 4 nipples on the engine and had no idea what to do with the 3rd one.
I am use to having 4 nipples on the engine and had no idea what to do with the 3rd one.
08-27-2008 | 11:00 PM
#9
RE: Four Stroke install help
At some point you may decide to do a little scale modelling. When you do, you can make tubes that look scale from some brass strap and tubing, and if you are careful, you can bell mouth the tubing. One of these is the fuel tank vent, and the other one is where I drain the oil catch tank.
Bill, AMA 4720
WACO Brotherhood #1
Bill, AMA 4720
WACO Brotherhood #1
08-28-2008 | 08:24 PM
#10
Senior Member
RE: Four Stroke install help
ORIGINAL: Stickbuilder
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
If you don't want the junk dripping out of the bottom of the cowl, drill and tap a nippple in the intake like a lot of the 4 strokes are using now and vent it there. In addition, use a velocity stack to hold in the blow back through the carb. I put one off the new O.S 56 on my O.S. 52, Same carb, and what a differenct under the cowl. I'm making some for my 70 and 91s now. Don't know if it runs better, but it sure runs cleaner.
Don
08-28-2008 | 09:07 PM
#11
My Feedback: (13)
RE: Four Stroke install help
here's what I did for the vent line,I epoxied a brass fuel tube to the bottom of the cowl,I leave enough slack so when mounting the cowl I just slide the fuel/vent line on it.
on mine I flush mounted the brass tube with the exterior of the cowl but you could leave a little extra outside and attach some more tubing to extend it past the surface, there isn't much oil coming from the crankcase vent line but a little extra tubing directs it off the fuse.
on mine I flush mounted the brass tube with the exterior of the cowl but you could leave a little extra outside and attach some more tubing to extend it past the surface, there isn't much oil coming from the crankcase vent line but a little extra tubing directs it off the fuse.
08-29-2008 | 03:01 AM
#12
RE: Four Stroke install help
ORIGINAL: Campgems
Bill, that may work on some engines, but other four strokes don't like the restriction even a little. One of our guys was using that setup on a Mag 52 four stroke. We just couldn't get the engine up to speed or down to idle. I finally had him just vent the crank and with out this minimual restriction, the engine run fine. I've seen serveral other post about restricting this vent and none claimed success.
If you don't want the junk dripping out of the bottom of the cowl, drill and tap a nippple in the intake like a lot of the 4 strokes are using now and vent it there. In addition, use a velocity stack to hold in the blow back through the carb. I put one off the new O.S 56 on my O.S. 52, Same carb, and what a differenct under the cowl. I'm making some for my 70 and 91s now. Don't know if it runs better, but it sure runs cleaner.
Don
ORIGINAL: Stickbuilder
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
If you don't want the junk dripping out of the bottom of the cowl, drill and tap a nippple in the intake like a lot of the 4 strokes are using now and vent it there. In addition, use a velocity stack to hold in the blow back through the carb. I put one off the new O.S 56 on my O.S. 52, Same carb, and what a differenct under the cowl. I'm making some for my 70 and 91s now. Don't know if it runs better, but it sure runs cleaner.
Don
I didn't quite follow your statement regarding restricting the vent. The method that I reccomended does not restrict the vent, but simply adds a large plenum that will allow the oil to collect. I'm sure that if you did manage to restrict the crankcase vent, then you would have problems. Now while I don't use engines of that size (my smallest is a Saito .91) I have never had a problem with this setup. My OS twins and flat 4's operate extremely well with it too.
Bill, AMA 4720
WACO Brotherhood #1
08-31-2008 | 01:27 AM
#13
Senior Member
RE: Four Stroke install help
ORIGINAL: Stickbuilder
Don,
I didn't quite follow your statement regarding restricting the vent. The method that I reccomended does not restrict the vent, but simply adds a large plenum that will allow the oil to collect. I'm sure that if you did manage to restrict the crankcase vent, then you would have problems. Now while I don't use engines of that size (my smallest is a Saito .91) I have never had a problem with this setup. My OS twins and flat 4's operate extremely well with it too.
Bill, AMA 4720
WACO Brotherhood #1
ORIGINAL: Campgems
Bill, that may work on some engines, but other four strokes don't like the restriction even a little. One of our guys was using that setup on a Mag 52 four stroke. We just couldn't get the engine up to speed or down to idle. I finally had him just vent the crank and with out this minimual restriction, the engine run fine. I've seen serveral other post about restricting this vent and none claimed success.
If you don't want the junk dripping out of the bottom of the cowl, drill and tap a nippple in the intake like a lot of the 4 strokes are using now and vent it there. In addition, use a velocity stack to hold in the blow back through the carb. I put one off the new O.S 56 on my O.S. 52, Same carb, and what a differenct under the cowl. I'm making some for my 70 and 91s now. Don't know if it runs better, but it sure runs cleaner.
Don
ORIGINAL: Stickbuilder
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
Here's a little helpful hint....If you have room in the cowl under the engine, find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it. When you are through flying for the day, pump the spent oil from the catch tank, and dispose of the gunky stuff properly. You would be surprised how much cleaner your plane stays, and how much easier the clean up is. Oh yeah, clamp the catch tank to the firewall, so it does not flop around inside the cowl.
Bill, AMA 4720
WACO Brotherhood #1
If you don't want the junk dripping out of the bottom of the cowl, drill and tap a nippple in the intake like a lot of the 4 strokes are using now and vent it there. In addition, use a velocity stack to hold in the blow back through the carb. I put one off the new O.S 56 on my O.S. 52, Same carb, and what a differenct under the cowl. I'm making some for my 70 and 91s now. Don't know if it runs better, but it sure runs cleaner.
Don
I didn't quite follow your statement regarding restricting the vent. The method that I reccomended does not restrict the vent, but simply adds a large plenum that will allow the oil to collect. I'm sure that if you did manage to restrict the crankcase vent, then you would have problems. Now while I don't use engines of that size (my smallest is a Saito .91) I have never had a problem with this setup. My OS twins and flat 4's operate extremely well with it too.
Bill, AMA 4720
WACO Brotherhood #1
Bill, he had a wad of cotton ball in the bottom of the vial. I am guessing that after one or two runs, it was saturated and causing the back pressure. Once he removed the vial and just exited the cowl with the vent, all was well. It was an older 52 Magnum, so age and hours may have played into the mix also. In any case, I vent mine outside the cowl with as short a line as possible. What's the old saying, your milage may vary
Don
08-31-2008 | 03:00 AM
#14
Senior Member
RE: Four Stroke install help
find a tiny tank, or use a small asprin bottle, and fit it with a tank plug. use 2 lines, fit one with a clunk and inside line. Run the vent tube from the engine crankcase vent to the vent tube in the small tank, and run a piece of fuel tubing from the clunk line to where you can access it.
Liked the idea enough to put a small bottle with some porous foam inside, laying on its side with intake in the cap and the outlet line coming out the high side and routing to a small diameter plastic tube running through the fuse and exiting aft. This is one a SPAD Tensor 4D oversized with OS 52 FS
