b7100 hard to start...

[demerson2]

just bought this 92 b7100 hst...was recently overhauled..(by a diesel mechanic that owned it).....all new bearings..new sleeves....heads redone...etc....you have to hold the glow plugs on for at least 30 seconds to get it to start....it seems to smoke alot at first(black smoke) but "planes out" to normal after 15-30 seconds...also it seems to have a "miss" during this time....after it catches up it runs good....not sure if this could be a "bad injector"?.....if that's what they have....timing off?.....weak glow plugs?...btw...it has a modified muffler(a straight pipe..lol).....not sure if the lack of back pressure of a real muffler would effect the running.....thanks for any insight

 

[Daren Todd]

Sounds like the glow plugs aren't working properly. And that would cause it to smoke and run rough, and also be a bear to start. I had a short in the wiring where the wires had come in contact with motor and melted down. Search this site for hard starting they have a ton of posts on the subject and with lots of good advise

 

[kc8fbl]

You might also want to try putting some fresh fuel with some type of injector cleaner. Seafoam, Stanadyne etc. Could be the glow plugs are tired as well.

Check your battery cables and make sure they have proper grounding.

 

[Piker]

My 1980 B7100 has always required a lot of glow plug time, 30 sec in warm weather, 1minin cold weather. Nature of the beast according to a lot of previous posts..

 

[North Idaho Wolfman]

Bet it's got some blow by, that lower the compression and makes it hard to start.
Might also need the valves adjusted that will make them hard to start too.
On a b7100 it's a indirect injection system so lot of glow plug time is the norm, I would OHM test the glow plugs and if any are out of the #'s replace them.
Also with the age and time the injectors they probably could use a rebuild and or replacement, but don't use cheap after market replacements they will just give you more problems!

 

[demerson2]

BTW...the decompression lever seems to not be working...the cable clamp isn't even on the cable...but when i manually pull it while its running it has no bearing on it running.....could this be part of my problem?....and why would this not be working?

 

[kubotasam]

I am starting to wonder if the "diesel mechanic" previous owner actually did any work to an old worn out engine. Or perhaps even worse made things worse by not properly doing the repairs. I would first take the valve cover off, set the valve clearance, then find out why the decompression does not effect the tractor. It does not need to be connected but when you move the lever it should stall the engine. Check for power to each glow plug with a meter. Check the resistance of each glow plug to see if it is open or shorted. Next a compression test will give a good indication of the condition of the valves and rings.