Glow plug health, how to tell?

TMB1320 · Jan 19, 2018

Here痴 my situation. I致e owned this tractor for five years now and lately it痴 been hard to start.
I知 would like to pull the glow plus on the Shibarua 1.3, but I知 hesitant because they致e been in there 20 plus years. They still individually measure low ohms (<2 ohms). I致e put upwards to 1000 hrs to the 3500 that was on it and the factory paint was still on the nuts on the bus bar feeding the plugs. I know there getting 10 v on both
Key switch positions, springy ccw from off, and cranking. The you boob shows these glowends can get incrusted
or frail to not come out with the barrel. Any insights what I might be up against here?

thepumpguysc · Jan 20, 2018

You wont know until you try.. personally I would spray the threads down w/ my favorite penetrating oil & give it a go the next day..
& depending on the type of meter your using, its been my experience that 2 ohms is fine. taking into consideration the resistance of the wire leads your meter..
IF you need an accurate reading, with the meter on, hold the 2 leads together & push the "delta" [triangle] button on the meter.. that will zero the meter w/ the resistance of the leads taken into consideration.

TMB1320 · Jan 20, 2018

Thanks for the reply. I was hoping to hear more on removal experience. Also on vid I saw showed that once the gp is completely removed, a straight reamer with grease in the flutes should be used to clean out the bore in the combustion chamber. Are there different size reamers?

kirkawilson · Jan 20, 2018

My FO-46 I&T Service Manual says: "To check continuity resistance of each glow plug, remove wiring connector from glow plugs and connect one test lead of the ohmmeter to glow plug terminal and connect other test lead to glow plug body. Normal resistance is 0.5 ohms for Models 1920 and 2120 and 0.8 ohms for all other models. Renew glow plug if there is high resistance (open circuit)." If yours measure less than 2 ohms, they should be OK. I would make sure that fuel flow is good (clean filter) before messing with the glow plugs.

KWentling · Jan 20, 2018

Only 10 Volts? I'd be cleaning connections. I would think you should have close to battery voltage.

TMB1320 · Jan 20, 2018

I’m ruling out filter for now as the feed from the tank to the fuel pump is gravity feed. The machine shows no sign of power loss under full load. That’s throwing snow 30 feet at 2500RPM. I have a spare filter but
I have yet to purchase a sight bowl gasket, which I think is really just an o-ring. Also I’m a little nervous about how to do the air bleed after it’s back together. Are there some tips on what works best to avoid having to crack the injector tube nuts. I see there is an air bleed on the filter body assembly, and also
on top of the banjo fitting inlet to the injector fuel pump.

For the 10 Volt measurement, I not surprised by this value considering the puny wire sizes used from the factory. It is a voltage drop that’s built in. I’ve seen clues on this forum elsewhere that adding a relay with some decent gauge wire directly connecting to battery, but I’m not convinced missing 1.5-2V is really going stop the show.

PILOON · Jan 20, 2018

"I知 not convinced missing 1.5-2V is really going stop the show. "

No, won't but will take a bit longer to glow hot is all.

On the other hand I believe that often they use 10 volt plugs on a 12 volt system probably to compensate for the voltage drop that occurs under high amp loads.

thepumpguysc · Jan 21, 2018

Loosen the screw at the filter & let it fill up & tighten..
Then loosen the screw at the injection pump until it fills.
The more fuel you have in the tank the faster & better off it'll go.
Then start the engine & hold the throttle off idle/half throttle for a minute or 2 until the air is out of the system. you'll hear it.
IF the engine wont start or dies after starting.. do it all over again.. don't burn up the starter.. just do the bleed procedure again & loosen the injector lines..
THERES NO SHORTCUT on getting air out.. well actually there is.. a can of ether or just keep cranking until you wear out the battery & burn up the starter & the wires.. its up to you.. Lol

TMB1320 · Jan 21, 2018

I was thinking a tip might be to open the air bleed on top of injector pump BEFORE removing filter bowl to avoid pulling fuel out (air in) the inj pump. Just a guess. Thanks for the reply.