Starting 6V-92TA

[DLCameron2]

Hi Guys:

Karl probably has a quick answer for this. Our port engine starts much better with the throttle "cracked" a little. That means when the engine fires up it is turning 1000RPM's or so, you can immediately slow it down to idle with no stalling or stumbling. Filters are good etc. Starboard starts fine with throttle "closed". I am wondering is this an indication that the rack on the port side needs a "tune-up" or is it something else. Your thoughts please. Thanks.

DC

 

[Boss Lady]

This is symptom of loss of compression. You add some fuel and after the first couple of revolutions the heated diesel vaporizes some volitiles and then fires up. I would guess that you have to spin it longer than the other before she lights off? If this is what you are seeing, you will begin to see more blue smoke in the exhaust. Maybe Karl will have better news, if you can get him away from Angela!

 

[MikeP]

I'd do a tune up and go from there if more is necessary. Re racks, I've found that it is not unusual for the two racks to operate slightly out of synch. Adjusting them so they are perfectly in synch takes a bit more care and double-checking than the service manual indicates.

When I bought our boat, one of the engines (8v71TI) was a bit "rough" running compared to the other. Turned out the racks were a bit out of synch, a couple of injectors were at the incorrect height and the buffer screw was improperly set. Additionally, the temps at the exh manifold exh ports one inch from the cyl head varied from port to port by as much as 75 degrees. After a tune up it was perfectly smooth and all exh port temps were within 15 degrees.

If you are somewhat mechanical and are interested, you can do all your own work on a DD (with the proper tools and the service manual). Some ability to curse is also a good additional skill, as it is for all mechanical work! I long ago learned that heavy cursing and "sneaking up on them" are two techniques that work very well for recalcitrant components. Using them in combination is especially effective in many cases!

 

[SKYCHENEY]

Don,
Is this just with a cold start? Once warm, they fire instantly, right? And I'll also assume that you don't have block heaters.

 

[DLCameron2]

Hello Sky....yes cold start only. I am sure the compression on Port is lower than STDB, however oil consumption, smoke etc. does not indicate a huge problem. No block heaters (yet) hahaha.

DC

 

[Boss Lady]

My 8v71Ns had gotten hard to start when the temp was below 50 degrees, one of them was starting to show some blue smoke. When they were torn down, there was no cross hatch on any of the cylinders, the one that was showing blue smoke required bumping the throttles and spin it on parallel batteries to start it. We got all the good out those motors.

 

[SKYCHENEY]

Don,
I wouldn't be too concerned. Mine both act similar to your port and both have about 3500hrs. You could have someone check the racks, but if that is the only symptom then I wouldn't bother with that expense right now. As our old mechanic at the shop used to say "If the wheels go round, drive it!". He was a stickler for keeping up with maintenance but a realist in that he wouldn't chase every little problem until it became something to really worry about. Funny how you learn what really is a problem when you're the guy that has to rebuild 'em if you make the wrong call.

I just bought a couple of the 250w Wolverine pad heaters for mine. The total cost was about $140. If you remember to turn them on a couple of hours before you startup, they start just like they do on a 90 degree day.

 

[Traveler 45C]

I just bought a couple of the 250w Wolverine pad heaters for mine. The total cost was about $140. If you remember to turn them on a couple of hours before you startup, they start just like they do on a 90 degree day.

they start just like they do on a 90 degree day....Even if it's 30F outside. Mine do with a puff of white smoke and that's it.
Before I installed those heaters though, OMG! They smoked huge for a very long time. It was embarrassing. Those slipped near me would close up their boats when I cranked up.

 

[Genesis]

Go through the entire tuneup procedure first. Odds are that's all you need.

If you have a rack that's sticking a bit or the banks are out of balance a bit it will do this sort of thing. You should never need to advance a throttle on a diesel when starting it, and in fact you never should do it as you're then going to start at above idle with no oil pressure for the first few seconds - not good.

 

[Brian Degulis]

Before you start it the rack is up near full fuel the moment it fires and begins to turn the governer brings it to idle. If the idle is set low or the buffer is out of adjustment it the governer may bring it to a below idle rack setting momentarily that's what shuts it down. At a minimum check the idle speed and buffer screw or better yet do the whole tune up. It's not a compression problem if it's fine after it starts.

Good Luck
Brian

 

[DLCameron2]

Thanks for all of the input guys I appreciate it!

DC