7.5KW Generac problems.

Question

I actually have two problems with this unit. It has a bit over 1K hours on it and has run thru 6 starters and still has problems starting at times. If I hit the preheat/fuel pump button for 15-30 seconds, it trurns over really slow and doesn't want to catch. If I crank it for a few seconds,it may start, but usually not. Then I'll hit the preheat button for 15 seconds, wait for a few seconds,hit the starter and away it'll go. Oh, and to do any of this I have to hit the battery boost button. Before they replaced the last starter,they found it was drawing 300amps. I'm thinking about putting a 12 volt battery right at the gennie and trying that. BUT, disconnecting the battery wires and puting my big 75 amp jumper box on it won't even turn it.
#2 problem is that It's not always putting power to the system. Unplug the shore power,set the power setting to 50 amps, start the gennie and 2 times out of the last 5 it sent power to the system. The closest place to me to get it really looked at is in North Bend,WA and I live on the other side of the water in Bremerton. Help.

gatorcq · Answer

Has anyone ever look at the cables and the battery stud where the cables are connected?Next what about the starter relay which along with the cables can cause an over excessive current draw.

dick_a · Answer

Jon, knowing your coach is a diesel I will assume ?? the generator is diesel also. If this is the case the generator starter will draw considerable current.

Going thru several starters and slow cranking is an indication low voltage at the starter when cranking. Use a voltmeter and measure the voltage at the starter Not cranking) and again with the starter cranking.

If the voltage is considerably lower when cranking then there is a DC wiring problem. Check ground strap from generator to ground for corrosion or rusty connections. Also, check the DC Plus wiring for any corroded or loose connections. Often a battery connection that at one time was corroded at the battery terminal will have corrosion in the copper strands inside the connector causing a high resistance (and voltage drop) under load.

You can buy an inexpensive induction current sensor at HF. If the cranking current is well above 125 amps there may be another problem.

Dick

mexicowanderer · Answer

300-amps is absurd. A Ford power-stroke engine demands the same amperage. Dick's advice above is great - I'd follow it.

A diesel with improper injection timing will fire before things are ready so keep that in mind. Some Designed-By-Idiot generators allow the prime mover to crank while the generator is seeing a load and has excitation enabled while cranking. This puts an unbearable load on the starter motor. That's another thing to watch out for.

bigdog · Answer

thanks guys. Looks as if it's out and under, again. Oh well, at least it's dry under there. It's just getting under and back out when you get wet.
Lessee, Notre Dame is at 9 AM and I think the Cougs are at 1:30, so that pretty much shoots tomorrow, so since the Thunderchickens are on a bye, it'll be Sunday.
Tuesday is gonna be spent heading for Ocean City St.Pk.for several days of R&R at the beach.

dick_a · Answer

Hey Jon, both our teems; Notre Dame and the Cougs won today! :)

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7.5KW Generac problems.

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