Almost started

  • Thread starter Peter J. Brennan
  • Start date
Status
Not open for further replies.
P

Peter J. Brennan

Hurth transmission (second). Always in reverse under sail. But forgot a few days ago and left it in forward after engine stopped. At seven knots under sail, the engine very nearly started. Would have had the throttle been open even a little bit. The sound of the turning shaft and engine brought prompt correction.
 
Jun 4, 2004
629
Sailboat - 48N x 89W
Neutral Switch

reference deleted :) I just don't believe that the freewheeling prop' had enough power to actually ("nearly") start the engine.
 
P

Peter J. Brennan

On a diesel?

A neutral switch? If the transmission is in gear and the boat is going fast enough for the propeller and shaft to revolve then the pistons are also reciprocating and ingesting air. If you also supply fuel in due course the engine will start. Not as if you are going to burn out the starter by cranking it too long. There might also be an issue with water ingestion through the exhaust manifold. After all, if my sails will drive the boat at up to eight knots and the best she can do at WOT under power is six knots, then there is a lot of extra horsepower being cranked into the engine.
 
P

Patrick

Agree again, Gord

I do not think that the prop will ever even come close to turning the engine. Neutral safety switch? I am reminded of left handed monkey wrenches, square hole drill bits, and Canadian Army tent wall straighteners. - Fond memories though they be...
 
Jun 4, 2004
629
Sailboat - 48N x 89W
power prop-engine?

Of course the neutral safety switch won’t have any effect on a freewheeling propeller-driven “start” - as Peter J. B. & Patric, rightly, point out - the N. switch merely prevents an electrical-start, when in gear. I don’t follow Peter’s analysis of speed under sail vs power (“... a lot of extra horsepower being cranked into the engine...”). Are you suggesting that much of the horse-power in a wind that will drive your boat to over 8 Kts, is actually transferred to your engine ?
 
P

Peter J. Brennan

Of course not

All that horsepower the sails generate will not be transferred to the engine. But if enough power is transmitted to the prop and gearbox so that the engine turns over in forward gear and the engine has air and fuel, it may very well start running. I have heard of this method of "jump-starting" a diesel -- with the engine free-wheeling in neutral, throw it into gear -- though I don't recall an irrefutable confirmation. But since many an older diesel had a hand strating lever, it makes sense to me. Not going to try it unless I have to since I would be concerned about water ingestion through the exhaust manifold.
 
Feb 6, 2004
83
CAL 25 Salem OH
Pop the Clutch

This would not be much different than popping the clutch on a rolling stick shift vehicle. If the engine is spinning, it will start. I somewhat agree with Gord though, it would take a lot to overcome the compression in a diesel. Not saying it couldn't happen. My SB8 has the hand start crank. Without the compression release lever I don't think I could turn it. Procedure is to hold the comp release, spin the he** out of the crank, release the lever while you are still turning the crank, try to get one or two more turns. Usually fires right up. Bryon
 

BarryL

.
May 21, 2004
1,115
Jeanneau Sun Odyssey 409 Mt. Sinai, NY
fuel pump

Hello, My engine (Universal M-18) has an electric fuel pump. If the engine is turned 'off' with the key, the fuel pump stops. Unless the key is ON, no matter how much the engine is turned, it's not going to start. Unless you have a mechanical fuel pump, there is no way to start the engine without the fuel pump energized. Barry
 
Feb 26, 2004
23,320
Catalina 34 224 Maple Bay, BC, Canada
Not Necessarily

Barry C34s also have electric fuel pumps. However, because of the height of the fuel tank above the engine, until the tank is half empty there is enough head to get fuel to the engine and it will work even if the fuel pump is off. I know, I read about it on our C34 website, and when my old fuel pump died a month ago, I topped off the tank and ran for two days without the fuel pump. Replaced with new fuel pump after that weekend. Stu
 
Status
Not open for further replies.