throttle position at start

btolle · Jan 30, 2005

( A good example of rated starts are stationary generator sets. All Caterpillar, Detroit Diesel and Cummins diesel powered gen sets have a pre-lube pump on them.)

Except emergency generators which I have installed a few of. They start at wide open throttle and only slow down enough to maintain the proper RPM to generate electricity. In that case wear on the engine is the least of their worries.

If I were in the middle of brain surgery when the lights went out I wouldn't want them to be more worried about a little wear on the generator engine than what's going on with the brain surgeon.

Now that I think about it motorhome generators, gas or diesel, start the same way, full throttle.

Bill Tolle

frank_f15 · Jan 30, 2005

( Whether it's my caterpillar or my Kubota, I always start it at the base idle and let it run for a moment before advancing the throttle. That applies to a cold or hot start.
)

That is just the way i do it, but could give such well described reason as you did. i start mine, just because it seems right to do it that way.

JJT · Jan 30, 2005

Cicso, That's he same procedure I've used for the past 6 yrs, 500 hours on my L3710. It always starts the first time, and it's still on the original battery. I did switch to Rotella 5W40 last year, it seems to crank faster when it's cold out.

DmansPadge · Jan 30, 2005

( Except emergency generators which I have installed a few of. They start at wide open throttle and only slow down enough to maintain the proper RPM to generate electricity. In that case wear on the engine is the least of their worries.)

You're right Bill. We have 10 or so backup generators at work, some diesel, some natural gas and they all start full speed ahead. That has always amazed me. Most of them are set on timers to run once or twice a week to keep them excersized but some of them will only crank a time or two a year and when they do.... look out! It sounds like they are fixing to explode! But they continue to run with no problems to any of them in the past 6 years I've worked there.

5030 · Jan 30, 2005

I really don't want to disagree with you, but you need to look at the control panel on the genset. I think you will find a pre-lube timed pump. I have never seen a commercial diesel powered genset that you could start instantly. Even my home standby unit (Generac Guardian propane powered) has a 10 second warm up before assuming the load. It don't have a pre-lube feature but it's a different animal altogether.

I was just up at Holt Caterpillar last week and looked at a large gen set mounted on a low boy trailer. It was an 8 cylinder twin turbo cat and like all the others I have seen, the startup cycle included a pre-lube. The do start at WOT, just like any Cat, but immediately drop to whatever rpm the generator head requires to maintain 60 hertz....before going online. Lets see, a 2pole generator head requires 3600, a 4 pole requires 1800. I'd say the head is a 4 pole. 1800 is right about where maximum horsepower is produced in todays 4 stroke diesels.

Again, I may be wrong, I am only human, but from my observances, I have never seen a large gen set without a pre-lube cycle. Dry starts are death for any engine, gas or diesel.

DmansPadge · Jan 30, 2005

5030, are we talking about a pump circulating oil before startup or a warmup period before being loaded? I totally agree that a dry start is death! But to be honest with you... we have several generators that as soon as the on switch is flipped it is cranking. They may turn over a few times before firing but no 10 sec delay. A few of the larger engines have an air operated pump to circulate oil through the engine before starting but that is still something that has to be done manually. I don't dought what you say... I'm just not sure if we are talking about the same things. Not to mention.... at our rinky dink operation the newest generator is probably 20 years old! /forums/images/graemlins/cool.gif

5030 · Jan 30, 2005

I am referring to large stationary or portable (trailer mounted) emergency or standby gensets in the 50Kw and up range.

The pre start sequence energizes a pre-lube pump that circulates lube oil in the engine before it starts. There is no warm up period to speak of other than they start, stabilize rpm and assume the load. The one I was looking at last week at the Cat dealer had about a 10 second energize to initial start at which time the lube pump energized, the electronic engine controls scanned all systems and then the unit started. They do start with a big puff of smoke. I was talking to the salesman and he went over to the control panel and energized the unit. I watched as the unit ran it's sequence and then started.....about 10 seconds or so. This was I believe a 100KW genset. Probably a little more than you need for home use.