• If you like antique engines, vintage tractors or old iron machinery, register and join us. When you register on Smokstak, please give complete answers and fill in the blanks. - IF YOU ARE ON WIRELESS OR SATELLITE, ENTER YOUR CITY AND STATE! NO ZIPCODES! All registrations are manually approved.

Onan 3.0AJ-1R/16017S generator starting difficulties

razorbac

Registered
Hi,
I'm new to the forum and have been fiddling with this genset for a couple of weeks, have gotten a lot of good information off this site but I' still stymied. It's in a 1979 Chinook motorhome with 140 hours on it and last ran 10 years ago.
Tried to start but no response. Solenoid tested bad.
Got ford solenoid and new battery cable to no avail and discovered through this forum that I needed onan solenoid.
One relay was marginal on ohms test so replaced all 3 relays and installed onan solenoid.
After the usual sat for 10 years fiddling, genset started and ran like a swiss watch.
Reinstalled into motorhome, started it a couple of times with no problems.
Tried to start a few hours later and it started right up, died and then wouldn't turn over.
Solenoid tested bad. I'm jumping battery lug to "S" terminal and no click but ignition terminal reads 12v and outgoing lug no voltage. I assume I did something stupid and bought a new solenoid but same result, doesn't turn over and solenoid doesn't shunt.
I'm sure I'm overlooking something simple, any ideas?gen1.JPGgen2.JPG
 

Wayne 440

Registered
(1) Obtain the diagram for your set and verify that all wires to and from the new solenoid are on the correct terminals.

(2) stop "jumping" things, and start trouble shooting based on the diagram.
 

Wayne 440

Registered
REMOVED - MY SET USES A DIFFERENT RELAY

I have edited your picture to show how the start relay in MY AJ works, yours may be different.

USE THIS INFORMATION AT YOUR OWN RISK.
 
Last edited:

RETCPO

Subscriber
Last Subscription Date
02/29/2020
Have you checked the TWO fuses?
Looks good will not conduct electricity!
 

razorbac

Registered
Have you checked the TWO fuses?
Looks good will not conduct electricity!
Yes, ohm checked the fuses.
View attachment 387237

I have edited your picture to show how the start relay in MY AJ works, yours may be different.

USE THIS INFORMATION AT YOUR OWN RISK.

RED- battery connection

BLUE- grounded when start switch is closed (energizes relay)

GREEN- these terminals close to RED when cranking.

As you might realize, "jumping" battery to a terminal that is designed for a ground input may cause damage.
Thanks, I see a potential problem and will trace it out tomorrow. I found a schematic that's mostly legible.
 

AlanR

Registered
Your schematic should be 611-1148, located on page 66 of manual 900-0186 here: http://www.skilledcrafting.com/onan...RV & AUX Genset Wiring Diagrams (06-1989).pdf

which shows the coil of the K1 start solenoid as isolated i.e. the coil runs from the S terminal to the I terminal, neither of which is tied to anything else in the start solenoid. Your power TO the coil comes from terminal 87A of K3, goes to terminal I, thru the coil, out terminal S, which is grounded by the start switch to complete the circuit and actuate the solenoid.

Alan
 

razorbac

Registered
Well, I have good news and bad news. The good news is, I traced the wiring,everything checked and the "S" terminal would ground with the start switch. Hooked up a battery and it spun over. Surprised me since it hasn't worked the last 25 times I tried it and I dropped my meter................ Tried it again and nothing happened. Disclaimer: I totally suck at electrical diagnosis. Anyhow fiddled with the switch trying to decide how best to test it and it started working again. Coincidence?
I had changed the relays previously and suspect the switch but I'm not 100% sure how to test it. Any ideas or logical way to proceed would be appreciated.
 

zuhnc

Subscriber
Last Subscription Date
12/08/2019
Substitute a different switch. SPDT, momentary/off/momentary. It is possible that the contacts were damaged using the Ford solenoid. zuhnc
 

razorbac

Registered
The switch ohmed out good and I haven't been able to duplicate the problem. I bet I benched tested it 50 times without fail. I'm getting pretty quick at R&R so put it back in the motorhome. Thanks to all for the great help, I learned a lot!
 
Top