1989 743 hard starting

[Jonny743]

Hello, in the process of buying an 1989 743(3500 hrs) and Need some advice.The guy im buying it off told me its very hard starting and has gotten worse in the 4 years he has owned it. He was using ether to start it every time summer and winter. I have personally looked it over and its getting fuel, checked glow plugs and relay and are ok. When it starts it gives a puff of black smoke then starts burning clean. When its running it works A-1 so im assuming all of the ether hasnt damaged the motor too severly. so if anyone has any ideas what it may be let me know. Like injectors,cracked head, rings?? any help would be greatly appreciated so i dont make the mistake of buying junk($5500).

 

[Tazza]

How did you check the plugs? did you remove them? they may be getting power and drawing current, but they may not be glowing to the tip.
The puff of smoke at startum is totally normal.
It could be low on compression too.

 

[Jonny743]

How did you check the plugs? did you remove them? they may be getting power and drawing current, but they may not be glowing to the tip.
The puff of smoke at startum is totally normal.
It could be low on compression too.

I removed them to test them. my thoughts were low compression as well, but it doesnt seem to turn over any faster than normal or have blow by on its rings as it doesnt burn oil(so the seller told me). aside from that ,what else would cause low compression? at this point would it hurt the machine to run it with the low compression, providing i dont start it with either like the previous owner?

 

[Tazza]

I removed them to test them. my thoughts were low compression as well, but it doesnt seem to turn over any faster than normal or have blow by on its rings as it doesnt burn oil(so the seller told me). aside from that ,what else would cause low compression? at this point would it hurt the machine to run it with the low compression, providing i dont start it with either like the previous owner?

Running on lower compression won't damage anything, its only harder to start and a lower power output.
Good idea about not using ether! just give it a longer glow.
I had a machine with over 6,500 hours, the glow plugs were burnt out, i put in a new set, it still took a good 30-60 second glow to get it running. When it was up, it would run all day, start with one flick of the key. If it starts and has power, don't be too concerned. I'd still do a compression test down the track, see if that is indeed the issue.

 

[doger5]

Running on lower compression won't damage anything, its only harder to start and a lower power output.
Good idea about not using ether! just give it a longer glow.
I had a machine with over 6,500 hours, the glow plugs were burnt out, i put in a new set, it still took a good 30-60 second glow to get it running. When it was up, it would run all day, start with one flick of the key. If it starts and has power, don't be too concerned. I'd still do a compression test down the track, see if that is indeed the issue.

Remove the manifold is the easiet way to change glow plugs trust me I have a 1988 743 also use high heat silicone to reinstall the manifold you probaly have to replace the exhaust bolts to the muffler