# Coleman 5500 generator (Briggs & Stratton) will not start - HELP please



## drjulian (Sep 28, 2017)

I have a 2 nearly identical Coleman 5500 generators from the 1990’s. Both have Briggs & Stratton 10 HP engines. During the recent power outage after Irma, I ran them both about 14 hours per day, turning them off at night to conserve gas.

After 8 days, one of the generators would not start, and I am at my wits end in trying to diagnose the problem. The 2nd generator works fine still.

Here is what I have done:
1. Verified that the fuel is good and the filter is clear
2. Verified that there is spark at the plug
3. In an attempt to isolate the problem, I exchanged the carb, coil and spark plug from the WORKING generator. The carb, spark plug and coil from the NON WORKING generator work perfectly in the WORKING generator. The know working carb, coil and spark plug from the WORKING generator, when placed in the NON WORKING generator do not solve the problem.
4. Verified there is oil in the engine, and overrode the low oil cut off to test.
5. Cleaned all the contacts on the on-off switch.
6. Sprayed starter fluid in the carb and actually poured a ½ cap of gas in the spark plug hole without success.
7. Opened the head and verified there are no head gasket leaks or cracks
8. Checked to ensure the piston is moving up and down and the valves are moving smoothly.

It seems like a fuel delivery issue since I have spark, but the starter fluid and manual pour of gas in the cylinder should allow a start if it is strictly a fuel problem (I would think)

I realize this is an old generator, but it gets limited use, normally less than once a year, and more importantly I have to figure out why it will not start or it will drive me nuts.

I am at the end of my diagnostic expertise in this.

Can someone direct me to the next step in figuring this frustrating problem.

Thank you


----------



## geogrubb (Jul 28, 2006)

As previously stated on the other forum check the flywheel key, it may be partially sheared and is firing but at the wrong time. Have a good one. Geo


----------



## finaprint (Jan 29, 2006)

You can have spark at the plug and it still not fire if partial spark is jumping down the side of the plug to not go 100% all of it through the air gap. . Plug MUST be both bone dry and not dark or black. Try running the plug gap a bit closer to make it easier to jump. 

If not getting so much as a pop out of starter fluid then likely not enough spark. If coil is type using airgap on flywheel then run that gap a bit tighter than spec as well, closer makes for a more pronounced ignition logic pulse. Do NOT make physical contact with moving parts! 

And for heavens sake stay away from gimmick plugs like E3, they are garbage! Use the correct replacement plug and heat range too. 

Yes, the thread is old but this stuff works for others coming later as well. Fouling plugs (and not being able to recognize them) is the most common owner induced issue there is on lawn equipment.


----------

