Besides for all that, some boats have wire runs long enough, thin enough, or 
corroded enough that the glow plugs will drop the battery voltage to where the 
starter solenoid won't activate and the starter button seemingly does nothing. 
I don't have glow plugs, but I did add an extra relay near the starter so the 
start button only has to pull that relay in instead of activating the solenoid. 
Works great :)

Joe Della Barba

From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Rick Brass
Sent: Thursday, May 16, 2013 10:41 PM
To: cnc-list@cnc-list.com
Subject: Re: Stus-List Starting a Universal

Some diesels don't use glow plugs. Normally they are direct injection and have 
higher compression than engines that use glow plugs. Requires a more powerful 
starter, faster crank speed, they are harder to start but easier to get 
compliance with emissions standards.

Engines with glow plugs are normally indirect injection. Plug heats the air in 
a pre-combustion passage in the cylinder head and hot air ignites the fuel. 
Easier starting (as long as the plugs work), lower injection pressures on pump 
and injectors, harder to get emissions compliance and complete combustion on 
cold start.

There are other systems as well. The new Ultra High pressure common rail 
Cummins engines (like you find in your pickup truck) have a heating grid in the 
air intake that heats the air in the intake manifold until the engine is up to 
temperature. DO NOT DO NOT DO NOT USE STARTING FLUID ON ONE OF THESE BECAUSE IT 
WILL FLASH BACK IN YOUR FACE.

The strangest system I've personally seen is on older Perkins 6-cylinder 
engines used in construction equipment and larger forklifts. It had a 
thermostatically controlled solenoid that bled hot fuel into the intake 
manifold. This enriched the mixture and aided starting. It also smoked like the 
devil and smelled like a refinery when the solenoid valve leaked - and they all 
leaked after a relatively short while.

Glow plugs or not is an engineering tradeoff made by manufacturers depending on 
costs, philosophy, and engine application, I don't think any Yanmar marine 
engine I know of uses glow plugs, but the 65HP 4 cylinder industrial engines do.


Rick Brass
Washington, NC



From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of David Risch
Sent: Thursday, May 16, 2013 7:58 AM
To: CNC CNC
Subject: Re: Stus-List Starting a Universal

OK...I gotta ask.

I have a 1981 3QM30.  Purrs like a kitten.

No glow plug.  Start up cold just fine.  Just a few more cranks.    Before this 
engine  I thought all diesels had glow plugs.

What gives?


David F. Risch
(401) 419-4650 (cell)

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