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Northstar 13000 Generator Smoke Issue - Solved

This whole situation is getting interesting.. and some of the culpability is on Honda.

I got the genny back, but under load, it would smoke a lot, although, the engine did not shut down. I noted no evidence of work being done, but I did note that the metal parts were rusty and the generator housing was corroded from weather exposure. When this left my home 3 months ago, it looked factory fresh.

I have been checking the dipstick numerous times to average out any error in sampling. The dipstick was slightly over the FULL line, as received back from Chatfield.

I decided to try something that I should have tried three months ago: stop trusting the dipstick as an accurate measure of oil level. Honda manual says to fill to the upper line on the dipstick. Well that's wrong, apparently. Upper line is overfilled.

On Friday, I drained a cup of oil from the crankcase, sealed it back up, and ran a load test. There was no smoke. After ten minutes, one of the 43A breakers tripped, so it was a real load test, a full 10kW or more. So this tells me that Honda's dipstick is defective. It is too short, or the marks are too high on the stick.

What I suspect happens is that the oil pressure increases under load, and increases even more when the exhaust back pressure increases just a little (such as running into a straight pipe to vent the fumes out of the building). So this overfill condition gets aggravated by heat, back pressure and load (which probably affects oil pressure).

I just wish I had not stubbornly believed that Honda's dipstick was accurate.

Did a second load test, this time with the car muffler in line with the long straight pipe. Also, shut off the Carver M500 amp. The engine did not smoke. The 'hook' on the AC waveform is gone. Apparently, mag field amplifiers pollute the entire electrical system. I'll have to design a line filter to clean that up. But it looks like the generator problems are finally solved. I'm going to write to Honda about the improper dipsticks they are putting in these engines.

Here's my followup to Northern Tool, on how I solved my generator problem when all the 'experts' could not:

"As a last resort, I decided to try an experiment and lower the oil level below the 'full' line on the dipstick. All along, I trusted Honda's specifications and their dipstick to be 'accurate'. Apparently, they are not. The Honda GX 630 engine calls for 2.1 quarts of oil capacity. The dipstick shows 'full' (filled to upper line) with slightly less than two quarts. This should be the proper amount of oil. But apparently it is not.

Today, I drained about 1/2 cup of oil from the crankcase, which took the reading on the dipstick to below 'full'. I ran the generator under full load and there was no recurrence of smoke. The engine happily kept running without complaint. My load was an electric clothes dryer (5200W plate rating) and an electric oven set to pre-heat (4700W plate rating). Both devices reached their thermostatic set temperatures after about 8 minutes of running, and the engine was fine.

We need to inform Honda that there is a problem with the calibration of their dipstick and a further problem with the oil capacity ratings.

Furthermore, Chatfield didn't do anything but let the generator sit in their yard. The elapsed hours meter hardly moved from where it was when they picked it up. I see no evidence that it'd been worked on at all. And they didn't know enough to try draining some oil to see if overfilling was the problem.

This teaches an important lesson: you can't always trust a specification and you can't trust that a dipstick is an accurate measure of oil level.

I'm only thankful that Chatfield didn't do any actual work on this unit, as they may screw it up with their incompetence. They charged for 2 gallons of gasoline that they never put in the tank. They claimed that they ran it for hours, but the elapsed time counter hardly moved from 3 months ago. They claim they rebuilt the carburetor, but I don't see any evidence that mechanical work was done. All they did was let it sit outside and get rusty.

I'm not a professional mechanic (though I did go to school for auto mechanics forty years ago, before I realized that I preferred working on electronics than engines), but after Chatfield did basically nothing, it took a last resort effort on my part to solve this problem. What a pathetic state of affairs. And the fact that I was deprived of the use of said generator for three months, that's a waste of my money."

And so ends the long saga (since June) of the Northern Tool Northstar generator. Now that this matter is resolved, I am happy with the unit.

Is there a part number engraved on the dip stick? If there is a part number, contact Honda and determine if the right dip stick was installed in the generator. I have heard of cases where the wrong dip stick resulting in overfilling the crankcase or the engine damage due to insufficient lubrication. If you can determine the correct crankcase capacity, drain the crankcase and then refill it with exactly the amount of oil specified in the engine manual. Then insert the dipstick and see if the oil is above, below or right on the full mark.

Wow, what an crazy adventure, I'm glad you were able to figure it out. I would have given up long ago!

Interesting - I have a lawnmower with a Honda engine.

To check oil level you have to do it with the dip stick unscrewed. Makes it easy to check, but can be confusing.

I'll take a look at the dipstick tomorrow, more closely. I don't recall seeing any number, but I wasn't looking for one at the time of the last oil check. One thing's for certain: it doesn't fit nicely into the receptacle where it goes. It is necessary to twist and turn it, while grabbing it halfway down its length to apply force to push it back down. A one-handed procedure, like with automobile engine dipsticks doesn't work due to mechanical interference on the way in. I thought that rather unusual, but figured it's just poor engineering.

There are vehicles like that. The oil is never where it belongs after an oil change and the proper amount of oil was used. They ended up scribing a new fill line on the stick.

Got a good, close up look at the dipstick today. No part numbers or identification print of any kind on it.
It's supposed to hit 80°F on Wednesday. Good day for a load test.

it should be 2.1 quarts including the oil in the oil filter, so if the oil filter was full, then you added 2.1 quarts of oil, that's overfilled. also, full is nearly to the top of the threads on the threaded type of oil plug, so with an extended oil fill tube, that would be nearly to the top of the bored out section of the crankcase for the oil fill tube.

I took that into account when I first added oil has received from the factory. I ended up putting less than 2 quarts of oil in because of that. My gauge when it was full was the dipstick so I filled it almost to the upper limit. That should be okay but apparently it is not.

If we were talking the same symptoms on a motorcycle.... We'd be discussing leaking Valve Stem guides.

My 1500 Goldwing, If slightly over-filled with Oil, and left on sidestand, will do the exact same thing on start.... (Blue Smoke). After it burns off, it's then fine! However, with same oil level, but bike left on center stand instead of side stand.... When it starts, it Doesn't Smoke...

It did that when new, also...
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Looking for 1939 Indian Motocycle

I often wondered why even being a 1/2 cup overfull would cause periodic smoke (every 15-20 seconds) under heavy load. And ONLY under heavy load. Granted, this is a new engine, hasn't been broken in yet, so maybe that stuff still needs to seat over use cycles. With the oil level just a tiny bit below the upper fill line, it seems to be fine now. As long as it continues to operate normally, I think it's probably just a matter of improper dip stick dimensions/seat depth. The dealer said that oil was being pushed back through the rebreather tube, and given the cyclical nature of the problem, it's consistent with slow buildup in the tube, then breaking of surface tension so that it flows into the carb suddenly. Tube empties out, engine runs fine until the next buildup of oil drops in the tube. Makes sense, if that's what's happening.