B7100 HSST 4WD won't start cold once it warms up it's ok

[philm]

Hi guys ,i'm new here although I have read many a article here relative to my kubota s ... my old B7100 HST has gotten hard to start over the last few months. i don't use it much anymore... i have a new L3301 i use for most work but have retired it to mowing the lawn and yard stuff.
ii replaced the heater plugs a while back and it seemed to help a bit when cold but now she won't start in the morning cold or warm without a small shot of ether ....i know bad bad for the engine... i only did it twice ... but without it all it does is puff white smoke and some gray and won't kick off... once she's running and warm ...starts right up ... any thoughts or insight would be appreciated for sure ..

 

[Roadworthy]

Check to see if you're getting any voltage to the glow plugs. Look for about 10.5 volts.. If you have twelve volts the glow plugs are probably bad. If you get no voltage you need to find out why.

 

[Dave_eng]

Hi guys ,i'm new here although I have read many a article here relative to my kubota s ... my old B7100 HST has gotten hard to start over the last few months. i don't use it much anymore... i have a new L3301 i use for most work but have retired it to mowing the lawn and yard stuff.
ii replaced the heater plugs a while back and it seemed to help a bit when cold but now she won't start in the morning cold or warm without a small shot of ether ....i know bad bad for the engine... i only did it twice ... but without it all it does is puff white smoke and some gray and won't kick off... once she's running and warm ...starts right up ... any thoughts or insight would be appreciated for sure ..

It is possible your use of ether has seriously damaged the engine.

Often, with the use of ether, connecting rods get bent which results in low compression.

I would guess before you replaced the glow plugs you used ether. Now, even with new glow plugs the engine does not have enough compression pressure to ignite the diesel fuel.

As a first step do a compression test on the engine. The glow plugs get removed and a special adapter screws in for the compression gauge,. A good engine will test between 398 & 454 psi.

Below 341 psi the engine needs serious work.

Dave

 

[philm]

It is possible your use of ether has seriously damaged the engine.

Often, with the use of ether, connecting rods get bent which results in low compression.

I would guess before you replaced the glow plugs you used ether. Now, even with new glow plugs the engine does not have enough compression pressure to ignite the diesel fuel.

As a first step do a compression test on the engine. The glow plugs get removed and a special adapter screws in for the compression gauge,. A good engine will test between 398 & 454 psi.

Below 341 psi the engine needs serious work.

View attachment 59539

Dave

actually never sed it before this ...so what ever this is...that wasn't it.

 

[philm]

Check to see if you're getting any voltage to the glow plugs. Look for about 10.5 volts.. If you have twelve volts the glow plugs are probably bad. If you get no voltage you need to find out why.

voltage was 13 after the new glow plugs went in .... i'm not sure if that's good ....i thought it was

 

[philm]

It is possible your use of ether has seriously damaged the engine.

Often, with the use of ether, connecting rods get bent which results in low compression.

I would guess before you replaced the glow plugs you used ether. Now, even with new glow plugs the engine does not have enough compression pressure to ignite the diesel fuel.

As a first step do a compression test on the engine. The glow plugs get removed and a special adapter screws in for the compression gauge,. A good engine will test between 398 & 454 psi.

Below 341 psi the engine needs serious work.

View attachment 59539

Dave

i'll try to run a compresion test this week .... like i said ...once it starts it will start all day long

 

[philm]

i'll try to run a compresion test this week .... like i said ...once it starts it will start all day long

the only other thing i have noticed is it burns more fuel that before ... powers still good ...she is a 1992 model but only has 300 hours

 

[philm]

thanks for the input guys !!!! ill let you know what i find out

 

[Dave_eng]

If your use of ether was very limited, then check valve clearances. Tight valves will bleed off compression pressure.

Has any wiring work been done on the tractor as 13 volts at the GP's is way too high?

The glow indicator, the glowing coil of wire on the dash, is a resistor wired in series with the three GP's and you should be seeing voltages more like 10.5

Dave

 

[07wingnut]

If your voltage at the glow plugs was 13 volts while you were glowing the engine, that is not good. A working glow plug will pull enough current to pull the voltage at the plug down below 12 or maybe 11 volts. On my bx23, the 3 plugs pull about 30 amps and drop the battery voltage down to 10.7 volts.

 

[philm]

If your use of ether was very limited, then check valve clearances. Tight valves will bleed off compression pressure.

Has any wiring work been done on the tractor as 13 volts at the GP's is way too high?

The glow indicator, the glowing coil of wire on the dash, is a resistor wired in series with the three GP's and you should be seeing voltages more like 10.5

Dave

i did not know that, this was my dads tractor i got it with 20 hours on it 30 years back and it has seen very little use, i always wondered why the glow plug indicator didn't glow.... i will also look at that .... i have had to very little to it over the years other than maintenance. it's a great machine. worth any repairs it needs

thanks
phil

 

[SDT]

Hi guys ,i'm new here although I have read many a article here relative to my kubota s ... my old B7100 HST has gotten hard to start over the last few months. i don't use it much anymore... i have a new L3301 i use for most work but have retired it to mowing the lawn and yard stuff.
ii replaced the heater plugs a while back and it seemed to help a bit when cold but now she won't start in the morning cold or warm without a small shot of ether ....i know bad bad for the engine... i only did it twice ... but without it all it does is puff white smoke and some gray and won't kick off... once she's running and warm ...starts right up ... any thoughts or insight would be appreciated for sure ..

Compression and cranking speed are vital.

At 300 hours, the engine should be in excellent condition absent abuse.

Judicious use of a small amount of ether once or twice should not hurt it but excessive and/or repeated use can result in addiction. Never heard of ether bending connecting rods but broken ring lands are a definite possibility.

As previously mentioned by others, 13V at the glow plugs is much too high. Should have about 10 - 10.5 VDC with plugs on and engine not cranking. Did you buy Kubota glow plugs? Have heard bad things about cheap aftermarket glow plugs. Glow plug indicator should glow but you may not see glow in sunlight. Something is not right.

Cranking speed must be appropriate. Battery, starter, and battery cables must be up to snuff to get good cranking speed. Again, at 300 hours, starter should be fine but check battery, battery cables and connections.

SDT

 

[Russell King]

If you have a decompression knob make sure that it is not bound up at all and returns fully when you release it. The lever that the cable pulls on can be pushed manually to see if it is able to be moved any further. It won’t hurt to spray that lever with penetrating oil where it goes into the motor housing (if you have one).

 

[philm]

hi folks ....thanks for all the responses ... after some discussions with my son and nephew it may have been run hot last summer a couple times ...which coincides with the issue begining. i got time to do a compression test today ...wet they all came in at 300psi much to my dismay .... oh well looks like sleves rings and pistons at a minimum...

 

[philm]

anyone have a source for a good engine rebuild kit ? i see them on ebay but since they are aftermarket i'm a bit leary.

thanks