Dick from Canada
Having problems again  with my Core Power unit on weekly self check. Last week it worked great, but this morning it misfired and coughed during it's entire running time . Thunder showers last night with lots of rain. I have installed a new ignition coil from Generac, no after market parts. Installed prior to last week. Today I rechecked the valve lash, regulator vent for spider,  spark plug gap [new plug] and for loose nuts as well as cracks in the intake manifold. All linkages are free as well as the throttle plate.   I put some dielectric grease on the joints of the ignition circuit. Started and ran great on manual start. Checked for moisture this morning before the exercise and found every thing dry.  In the past with this problem we get a good start even after two or three days sitting .  It takes about a week for it to act up. Rain tonight , will see what happens in the morning on a manual start. I wish something would just break, this kind of problem is very frustrating.  Thanking you for your thoughts.
Quote
78buckshot
Dick, I scanned through some of your original posts on this subject. Can you describe the fuel supply set-up, I didn't look through all the previous posts for info on it. I did see in one that a tech said fuel pressure was ok and that you did not have a manometer to make any tests. I assume you are on 2psi natural gas given some of the prior info and that you have a dedicated regulator for the generator, is this correct?
Quote
Dick from Canada
The fuel supply comes after the regulator at the house hold gas metering station . There is about 15 ft of 3/4 inch line and then goes under ground for a about 5ft. The initial job was done by licenced gas fitters. Although there is no way of telling if there is an leak underground letting in water, I know that a even a small leak will kill any grass above it. There is only a gas hot water heater and furnace in the house. There have been no problems with any of these. In the past the generator has run fine with both water heater and furnace running. On Mondays self check non of these were running. As you know the unit has it's own internal regulator .  When I installed the unit I ran some numbers and there is more than enough capacity from the gas utility .  Hope this is of some help. Pouring rain right now , and will give it manual start as soon as it dries up a bit. Yesterday when I did my checks I tightened the manifold nuts 1/2 turn as they felt loose . Could there have been air sucking in ?  One has to be careful here as every thing is plastic. 
Quote
78buckshot
Ok, now I'm getting a better idea of the gas, it sounds very conventional. It would be good to know the pressure at the generator with it not running and another read with it running. I agree with you that the meter and piping should be adequate. The regulator can creep with age and most are adjustable. Any chance you can check the pressure?
Quote
Dick from Canada
Will scout for a  gauge . We can get a reading at the BBQ tap , not used but has a valve and screwed fitting. Started perfectly  today even after rain all night and this morning.I'll keep in touch.
Quote
78buckshot
Does the piping outside of the generator have a drip leg? that is an easy spot to take a reading and will tell us more than at a fitting up the line.
Quote
Peddler
The demand regulator on some of those had a vent that was prone to getting clogged by mud daubers.  That is where the gas comes in and is metered to the engine.
Quote
Dick from Canada
There is a drip leg . Even closer than the BBQ fitting .  A better source to measure the pressure. The vent line from the regulator is clean . Will scout for a pressure gauge tomorrow.  When you said that the regulator may creep did you mean the one in the generator or the household .  The one at the house is made by Fisher  Controls . I have always found these to be very reliable . 
Quote
78buckshot
The one in the generator is not designed to regulate the pressure and has no adjustment, it is a vacume controlled valve that allows the gas to flow when the engine is cranking and running. The regulator at the gas meter should be adjustable and the normal setting is 7.5 in. water column. If you can find an inexpensive water tube manometer that will be all you need to check the pressure, or a dial gage in inches of water column. I have adjusted many natural gas and LP regulators and have requested the gas company/LP supplier to replace those that won't hold steady or won't adjust to the correct pressure.
Quote
Dick from Canada
Thanks for the info, most useful. I have got a 0/ 30 psi gauge from a friend. I was not aware that the pressure was that low . Thought maybe 2/ 3 psi . Will look for a water column manometer or inches of water gauge . May take a little time.
Quote
78buckshot
You can make one but it takes more time than it's worth, $10 will get you a water tube. Check Yellow Jacket or Dwyer. One psi= aprox. 28 - 29 inches of water column so natural gas at 7.5 in. w.c. = aprox. 1/4psi. Each of the appliances in your house has it's own gas valve and regulator and normal manifold pressure is set at 3.5 in. w.c. for natural gas, 10 - 11 in. for LP. I'm just including those numbers to give a little comparison
Quote
78buckshot
Ok, so Covid has the cost of things wacked out. Yellow Jacket #78075 manometer $25 - $30, if you have a little time you can google how to make one. Don't get anything more than this, the electronic and dial gages are nice but the water tube doe's not lie, water can't go out of calibration.
Quote
Dick from Canada
Should have checked your post this morning . I was an instrument mechanic before retiring.  Made one this morning using some Tygon tubing and a flat board. Made a U and fastened it down on a board and made a scale of 12" up and 12" down , zero in the center of coarse, and filled with water at zero. The results were 8.5 inches on gas line . Started the generator [ perfect start] ,by turning off the utility power to the sub panel and put a 1500 watt space heater on each phase plus whatever was running in the house. Pressure dropped to 8.25 inches. The pressure was nice and steady.  Should be good ,but when I removed the drip tube I found a small amount of insulation. This may have migrated to the internal regulator, hope not . Quite a chore to take it all apart.  Will  look on line for a proper manometer , nice to have one .  Keep the space heaters just for that purpose.
Quote
78buckshot
Your home-built manometer is as good as a store -bought one and you probably won't use one very much. The insulation in the gas line could be the issue if it has partly obstructed something. I would lower the static pressure to 7 - 7.5 inches if I were on site. Just to make sure I'm understanding ( I'm sure you know it) did you read 4.25 in. up on one leg and 4.25 in. down on the other leg of the gage?
Quote
Dick from Canada
Yes that is the way it was read . Have to keep the board level . Am reluctant to set the gas company regulator but I will call them Friday  They are usually good with any issues. Just a bit of info, the Yellow Jacket manometer is $50 on Amazon Ca  but out of stock,. Will hang on to the home made one.
Quote
78buckshot
Do you get charged for a visit from the gas company?, if not then let them adjust it.
Quote
Dick from Canada
No charges as the metering and regulator belong to them .
Quote
Dick from Canada
Thinking of removing the fuel solenoid  to check for insulation as in the drip leg . Will I be left with springs and other parts or does it come out as a complete unit? Service manual does not say or show pictures . I know it is not faulty . Manual says just to replace, as long as I'm not left with a hand full of  springs and other parts with only a guess on how it came apart. 
Quote
78buckshot
The solenoid has one light spring and a plunger after removing the four phillips screws, the demand regulator has a diaphram, lever, and spring. I would disassemble them and check it.
Quote
Dick from Canada
Demand regulator , fuel solenoid and all lines to the carb,including the flow restrictor were clean . Gas company was in today and found the pressure to be as we read it at 8.5 in of water at the input to the demand controller . They  installed a new regulator . Was told that they do not adjust them as it was "old " . Pressure now reads 7.5 inches H2O.  Started perfectly and runs well. Will see what happens after it sits till Monday on it's exercise run. Thanks for all the help and advice.  
Quote
78buckshot
Thanks for the follow-up, I hope it proves to be the culprit.
Quote