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50/50/90 rule

Posted: Sat Nov 29, 2014 8:32 pm
by Once and Future
Are you familiar with this rule? It states if you have to make a blind choice, with a 50/50 chance of being right, you will be wrong 90% of the time. And it came true for me again today. Now that I have my stove humming, I decided to install an emergency high-temp shut-off. And while I was at it, a friend noticed I did not have an easy access clean-out "tee" fitting in the 3/8" tubing that connects the carb to the burner pot. So I elected to install one. Especially since the tube was plugged when I went to relight the stove.

So, trip to hardware store to pick up 3/8" flare nuts, etc. And I should know better. The new flare nuts indeed fit 3/8" tubing, and thread on the fitting. But only once I had them installed finger tight did I learn the wrenches wouldn't fit them. In between 3/4" and 11/16". (China, anybody?) So, crescent wrench. Except. Crescent wrench won't fit where I put them. Right under the burner pot. Absent knowing the wrenches would not fit, I could have got lucky and put the OLD flare nuts in the inaccessible place. But no, I happened to put them right below the carb. 50/50/90 rule. (Of course I re-used the old flare nuts because I was raised by depression-era parents.) So I had to back up, cut off the flares, switch around flare nuts. Another hour lost. Is it only me that has to fight EVERY project tooth and nail?

Finally got connected with no leaks. Of course I have been unable to get my emergency shut-off to trip as per the directions. But that is a different issue.

Re: 50/50/90 rule

Posted: Sat Dec 13, 2014 5:09 am
by Trnaround
No it's not just you, but you sure remember the projects that make you struggle especially when it seems like it's going to be easy. Question, what type of emergency shut off did you use? Did you use the one Dickinson makes or another type?

Re: 50/50/90 rule

Posted: Sat Dec 13, 2014 8:51 am
by Once and Future
Yes, I used the Dickinson offering since it didn't need to have power run to it and Dickinson seems to make good stuff. Hamilton marine had two left on closeout for about $100.

Takes a long time to calibrate the darn thing. (Let stove heat up for couple hours, let device trip, let stove cool back down, move sensor a little, reset device, let stove heat back up, repeat.) Plus you have to be so careful of thermocouple tubing. I installed the valve right next to my carb, but the fact that two adapters are required (included) to convert the device from British pipe thread to North American pipe thread makes the device bigger than it needs to be.

I don't know what else is available on the market. But if you were able to buy a device that did not require the calibration, it would probably be easier to run 12v power to it, than calibrate the Dickinson model, if that's what was required.

Re: 50/50/90 rule

Posted: Sat Dec 13, 2014 8:51 pm
by Trnaround
Ya I see, I was looking at the Dickinson solution too and it seemed complex. Anyone know of other options? Thanks

Re: 50/50/90 rule

Posted: Sun Dec 14, 2014 8:43 am
by SalmonSeeker
Maybe try 18mm.

Re: 50/50/90 rule

Posted: Sun Dec 14, 2014 1:20 pm
by Once and Future
@salmonseeker: I thought of that, but I've been able to get by on the boat so far without metric wrenches. So I would have lost 45 minutes going up town to buy one. Plus then I would have even more tools to find a place for on the boat, and something to remember about the installation. I opted to switch the flare nuts around instead...
Was just ticked I didn't accidentally put the flare nuts in the lucky order the first time.