bench starting a engine. NO NEVER
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bench starting a engine. NO NEVER
I know everyone here has the own opinion in bench starting. Or even what it is. When I talk about bench starting ,everything's together . engine in the boat mount, prop shaft in, turning a boat prop. Radio working . I run a engine just long enough, as I was at the pond ready to launch . 20-30 sec. tops . Not in VISE turning a airplane prop . Some refer to it that way just my opinion. Do you call it bench starting or pre-start? A new engine is very hard to start. open the plug, still hard then what ? when we say bench start what is it ?
#2
RE: bench starting a engine. NO NEVER
For one thing, it's very hard on the boat and hardware. I blew the rod and case on a K&B .45 years ago doing that, never again. It was a new engine and I had to lean it out to keep it running at the lower speeds I wanted to break it in at. Live and learn I guess
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RE: bench starting a engine. NO NEVER
Good way to break-in an engine IMO. Since I mod engines all the time (21's thru .30's mostly) I break them in on the bench most of the way. If a customer wants it test run on a boat then thats what they get. I can usually get the needle very close so he doesn't have to spend a lot of time finding the needle for his hood.
The method I use the radio system is on the bench turned off, it won't be needed until the sixth or seventh tank. I go for 1/3rd carb opening, needles set rich, very rich. I choke and by pinching the fuel line I'll get the starter going with that fixed 1/3rd carb opening.
Some times too much fuel will accumulate in the muffler or pipe,, put hemostats on the fuel line and dump it out.
Go back to pinch and starter,, once its going the richness will want to kill it,, pinch or pinch in succession to keep it alive. You now are the fuel metering for the engine. I use a heat gun in one hand and the other is the pincher. I keep the them down to 125* on the first couple thanks and move higher with each tank. You can run the needle "in" a couple clicks if you have to pinch steadily. later in the tanks its up to 175*- 185* and up and I'll pinch it to run up in rpms and let the richness bring it back down.
In muffler engines like the O.S.XM o/b and Thunder Tiger its possible to get a runaway in rpms cause of the no limiting factor the muffled engines have. They'll just feed off their own creation of fuel pressure and heat and become a runaway jet turbine. Not to be worry tho, your the one metering the fuel,, just brush the carb opening with your finger and choke it back down. around the 7th tank you can pick-up and turn on the transmitter with most engines and get your needle limits roughly set.
All this is done with more fuel and lube than that engine will ever see in normal operation. Your also building important heat and monitoring it. You want the engine to swell and run-in its surfaces where necessary in a safe lubricated manner. Every auto engine comes with a thermostat and most are set to open the cooling at around 190*. If its important to a car, trust me, its important to your little model engine.
uhhh,,"bench starting"?,, you must be talking about something else. anyway you have a great method of breaking-in the engine here.
The method I use the radio system is on the bench turned off, it won't be needed until the sixth or seventh tank. I go for 1/3rd carb opening, needles set rich, very rich. I choke and by pinching the fuel line I'll get the starter going with that fixed 1/3rd carb opening.
Some times too much fuel will accumulate in the muffler or pipe,, put hemostats on the fuel line and dump it out.
Go back to pinch and starter,, once its going the richness will want to kill it,, pinch or pinch in succession to keep it alive. You now are the fuel metering for the engine. I use a heat gun in one hand and the other is the pincher. I keep the them down to 125* on the first couple thanks and move higher with each tank. You can run the needle "in" a couple clicks if you have to pinch steadily. later in the tanks its up to 175*- 185* and up and I'll pinch it to run up in rpms and let the richness bring it back down.
In muffler engines like the O.S.XM o/b and Thunder Tiger its possible to get a runaway in rpms cause of the no limiting factor the muffled engines have. They'll just feed off their own creation of fuel pressure and heat and become a runaway jet turbine. Not to be worry tho, your the one metering the fuel,, just brush the carb opening with your finger and choke it back down. around the 7th tank you can pick-up and turn on the transmitter with most engines and get your needle limits roughly set.
All this is done with more fuel and lube than that engine will ever see in normal operation. Your also building important heat and monitoring it. You want the engine to swell and run-in its surfaces where necessary in a safe lubricated manner. Every auto engine comes with a thermostat and most are set to open the cooling at around 190*. If its important to a car, trust me, its important to your little model engine.
uhhh,,"bench starting"?,, you must be talking about something else. anyway you have a great method of breaking-in the engine here.
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RE: bench starting a engine. NO NEVER
I have ran a full tank of nitro through my boat out of the water, I just make sure that I have water flowing to the water pick up & I will pull the flex shaft out so the bushings don't wear from getting hot. I have no problems doing this at all. I like to make sure that everything is in good working order before I get to the pond.
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RE: bench starting a engine. NO NEVER
I do it similar to JW. I have a valve on the garden hose to supply just a trickle of water to somewhat simulate a running environment. Then I heat Cycle the engine as JW does by leaning and richining and running rpm's up and down. Never go over 1\4 to 1\3 throttle without a load on the engine. I run a minimum of 3 tanks before hitting the pond, Normally 4 to 5 tanks.
I also use straight Klotz Benol(castor oil) no Synthetic for the first half dozen tanks of fuel. The synthetic oil provides to slick of a surface for the moving parts to Lap into each other properly, also Synthetic oil tends to move Away from Hot Spots where Castor moves to Hot Spots. Hot spots are caused by a Tight Fit in Some areas of the sleeve, tight fit = more Friction= Heat. The synthetic oil will move away from hot spots and let them get hotter or even seize
I also use straight Klotz Benol(castor oil) no Synthetic for the first half dozen tanks of fuel. The synthetic oil provides to slick of a surface for the moving parts to Lap into each other properly, also Synthetic oil tends to move Away from Hot Spots where Castor moves to Hot Spots. Hot spots are caused by a Tight Fit in Some areas of the sleeve, tight fit = more Friction= Heat. The synthetic oil will move away from hot spots and let them get hotter or even seize
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RE: bench starting a engine. NO NEVER
yeah your likely doin' that to I/B engines, the water on that is. The o/b's have that lower unit on there and its a big heat sink, its easy to do it w/o water on those.
I guess I should have made that point clear in the begining.
JW
I guess I should have made that point clear in the begining.
JW
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RE: bench starting a engine. NO NEVER
Yep, I haven't messed with O\B's Yet. I have an Old Tunnel boat with an Ancient K&B .21 that needs rebuilding,,and that was as far as I got with it,,LOL. I like my hydro's.
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RE: bench starting a engine. NO NEVER
'when I hear" bench start" a bench vice comes to mind .The first engine I ever had I blew the con-rod. my flex cable was loose. She screamed for a few seconds & snapped that rod .fast before I new what to do .
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RE: bench starting a engine. NO NEVER
I have never used the Bench and Plane prop method myself, but have talked to others that have used it. If you get a prop that Simulates the Same Load as your boat would, it works very well. You can actually get a prety close tune on the engine Before hitting The Pond
Any time you start an engine with No Load on it, Make Sure ALL the air bubbles are out of the fuel line, so it doesn't Lean Out and instantly Scream.
Any time you start an engine with No Load on it, Make Sure ALL the air bubbles are out of the fuel line, so it doesn't Lean Out and instantly Scream.