run away revs on starting

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kerry boden's picture
kerry boden
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Joined: 8/1/11
Posts: 41
run away revs on starting

Hi all,
I have a real problem with my M35 engine at the moment.
I want to start the motor as usual, with the gears in neutral and the revs at idle.
I turned the key to heat the glow plugs, waited and then started the engine.
As soon as it fired the revs increased like crazy, although the throttle was still at idle (and proved to be the case after the incident).
I was stunned for a split second and grabbed for the fuel shut off handle and pulled. At first it seemed innefective until I really pulled it hard.
The engine shut down and I stopped panicking.

After a good while and a steadying drink I decided to try again.  With some trepidation I went through the start procedure, but no joy, the engine turned over but would not start.  I found no fuel was getting through to the injectors.

I went through the entire fuel system and found no fault.  The fuel was being pumped to the fuel pump and flowing through the fuel return system, but nothing flowing through the injector pump itself.
Before I tackle the problem I  wondered if  anyone else had this occur and if so what was the result?
Look forward to hearing

Kerry

Kerry Boden

 

TomR's picture
TomR
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Joined: 12/4/17
Posts: 38

Kerry,

Sounds like you may need to have your injector fuel pump pulled & rebuild. Last season I had water in my fuel, so much so, that it overwhelmed my Racor filter and siezed my pump. No fuel got to my injectors. Pump was rusted inoperable. They can be rebuilt. Take it to a reputable service place. The specs & tolerances as such you cannot do it your self.
I am paranoid about my fuel now. Always checking my filters and have plenty of spares.

Tom R
ObLaDi ObLaDa, C36MkII 1989

  
 

Tom Runiewicz
ObLaDi ObLaDa
Catalina 36 MkII, Wing Keel, Tall Rig
Hull #1998
North East, MD
 

Parsons's picture
Parsons
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Joined: 6/2/16
Posts: 95

You may have a real problem which I've heard of, but never seen.  If you lose compression due to leaking rings, you could burn the lubricating engine oil, rather than fuel oil.  How many hours on this engine, and have you lost engine oil in your sump?  I would not try to start this again until you have a real diesel mechanic validate compression.  At its worst, I understand that you simply cannot shut the engine off because the fuel cutoff has no effect. The engine just runs away until it siezes.

John Parsons
"Water Music" 1999 Catalina 36 Mk II - Hull 1771
Tall Rig, Fin Keel
Bay City, MI, USA

Catboat Willy's picture
Catboat Willy
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Joined: 12/22/14
Posts: 385

Kerry, 
I did have a old VW Rabbit diesel years ago that did exactly what John describes above. On a five hour drive, the engine started to speed up and there was no way to turn it off ! The car's engine  kept going faster and faster, not understanding what was happening, I wore out a set of brakes trying to keep a reasonable speed. Upon analysis at the VW dealer/service center, the mechanic describled the exact situation that John speaks to above.
 In a diesel engine with very worn rings, lubricating oil is sucked up from the crank case and burned as fuel.
I would certainly do as John suggested and get a diesel mechanic to test the compression before re-starting the engine. You may need a rebuild. of the rings.
If it does happen again; try removing the air filter and put your hand over the air intake to stop air being drawn into the engine. That just might stop it from running away. Let us know what you find......
 

Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte  Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'

 

kerry boden's picture
kerry boden
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Joined: 8/1/11
Posts: 41

Problem Solved!!!

The rack in the injector pump was sticking intermittently.
It must have stuck fully open to give me the scare on starting, then when I shut it off it stuck at fully closed and therefore would not start.

My mechanic said that everything was in really good condition, except for the sticking rack.  The pump service people said that the bosch pump will occasionally have this problem, for no apparent reason.  However, with pump fully serviced and reinstalled all systems go.
 
cheers
Kerry

Kerry Boden

 

Catboat Willy's picture
Catboat Willy
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Joined: 12/22/14
Posts: 385

Kerry,
 Glad you got that issued resolved and thanks for sharing your findings with the group.
Smooth sailing !
Bill

Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte  Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'

 

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