Onan gen-set ran for a minute......I need a manual

[Guy an a dog]

I'm working on an Onan 4.0 BF-CR/16000B gen set in my 1977 The Diplomat II
This is the first time Ive ever run this gen set and it says it has 337 hours

Today I drained the old oil and put in 4 new quarts of 30w, I changed the air filter and attached a boat gas can the the fuel pump inlet because the fuel in the tank is 3-4 years old and I think has some watter in there too. A few cranks and it fired right up

it ran well for about a minute and then died it started back up and ran for a few seconds and died again I pulled a spark plug and checked for spark but no spark, so I went to pull the plug wires off the coil and they broke off. Off to the Napa thats a block down the street to get two new spark plugs and two new plug wires. I get the new wires on and get the plugs gapped and then check for spark again but no spark. I figure the next thing to test is the coil so I take that off and test the primary side and get .04 ohms I test the secondary side and nothing. I figure I need a new coil and I might as well replace the points too.

I feel like I'm flying blind without a manual and I can't find one online when I look. Does anybody have any suggestions about the gen set or where to download or find any type of manual for this thing? Any help would be appreciated.

[whem2fish]

your gen looks like mine did you do the points, i do have a generic manual ill get out to the rv and see where i bought it

[rewaters49]

Here's a link to a forum for older engines: Antique Engines and Old Iron Tractors on SmokStak

One of the guys there emailed me a manual for my Onan Emerald. I bet they'll have something for yours, too. Good luck!

[Senior Chief]

Is this the manual you need?

[wa8yxm]

If the engine starts and runs for a minute I suspect it's not the points, or plugs, else it would not start,, More likley it is the generator, fuel system, or computer, yes, it has a computer.

Fuel system: A clogged filter will let gas through slowly, but after it runs a bit the fuel will not be flowing fast enough,, Likewise a bad fuel pump may not pump enough to meet the needs.

Generator.. Onan senses if it's outputting 120vac, if it's not, or if the output is out of specification it shuts down, either to save fuel or to protect your down-line power consumers.

Computer: Makes that decision.

Now, finding out which it is is beyond my remote ability but hooking a voltmeter to the output leads might well be the first step.

Also, make sure you have good 12vdc to it.. Same powers the fuel pump.

[Guy an a dog]

Originally Posted by Senior Chief

Is this the manual you need?

Yes I believe thats it. Thanks so much

[Guy an a dog]

Originally Posted by wa8yxm

If the engine starts and runs for a minute I suspect it's not the points, or plugs, else it would not start,, More likley it is the generator, fuel system, or computer, yes, it has a computer.

Fuel system: A clogged filter will let gas through slowly, but after it runs a bit the fuel will not be flowing fast enough,, Likewise a bad fuel pump may not pump enough to meet the needs.

Generator.. Onan senses if it's outputting 120vac, if it's not, or if the output is out of specification it shuts down, either to save fuel or to protect your down-line power consumers.

Computer: Makes that decision.

Now, finding out which it is is beyond my remote ability but hooking a voltmeter to the output leads might well be the first step.

Also, make sure you have good 12vdc to it.. Same powers the fuel pump.

The coil is testing bad so that will be the next to replace.

[whem2fish]

hope it works out if not pm me il give you my phone number

[Guy an a dog]

Originally Posted by whem2fish

hope it works out if not pm me il give you my phone number

Ok will do. I need to hunt down a replacement and the RV place down the street is closed until tuesday.

I would think that the service department at an RV dealership would be open for business on the most popular camping weekend of the year

Any one have a suggestion on a good/cheap website for parts?

[Guy an a dog]

Originally Posted by wa8yxm

If the engine starts and runs for a minute I suspect it's not the points, or plugs, else it would not start,, More likley it is the generator, fuel system, or computer, yes, it has a computer.

Fuel system: A clogged filter will let gas through slowly, but after it runs a bit the fuel will not be flowing fast enough,, Likewise a bad fuel pump may not pump enough to meet the needs.

Generator.. Onan senses if it's outputting 120vac, if it's not, or if the output is out of specification it shuts down, either to save fuel or to protect your down-line power consumers.

Computer: Makes that decision.

Now, finding out which it is is beyond my remote ability but hooking a voltmeter to the output leads might well be the first step.

Also, make sure you have good 12vdc to it.. Same powers the fuel pump.

I didn't think it was the plugs ether but they didn't look good and were only a few $ to replace. The wires were brittle and broke off and only $5 for the pair. It does need a new coil and I figured the only thing left in the ignition system that wouldn't be new would be the points so why not them too.

If it doesn't run after I replace the coil I'll look at the rest. Thanks for the advice this is my first generator so other than that the general basics I'm kinda lost.....but I'm a quick learner.

[mrblanche]

What does the coil look like? It may be possible to use a different item if you know the specifications.

It's not a bad idea to replace the plugs right off the bat. The unit we have is very sensitive to any wear at all on the plugs.

[QuietWater]

Here's another place to get an owners manual. It's a direct pdf file with no advertising involved.
http://f1.grp.yahoofs.com/v1/wMThTZc...F%20Manual.pdf

[steved44]

Make sure and replace the condenser too. My onan in my boat had that problem and it turned out to be the condenser, after I had changed plugs, points, coil. It would run for a few minutes or maybe just not start. Good luck Steve

[Guy an a dog]

Originally Posted by mrblanche

What does the coil look like? It may be possible to use a different item if you know the specifications.

It's not a bad idea to replace the plugs right off the bat. The unit we have is very sensitive to any wear at all on the plugs.

The coil looks like a normal round automotive coil from the 70's but it has two plug wires plugged into it rather than one. It is a waisted spark system so it fires both at the same time.