Predator 8750 generate will not start - Power Equipment Forum : Power Equipment Forums
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Old 05-10-2019, 04:56 PM Thread Starter
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Predator 8750 generate will not start

My generator will not crank. I normally run it at least once a month for 15 minutes, or so. I use standard 87 octane gasoline, which has ethanol in it, with Stabil. A month ago, I went to crank it and it did this.


I've tried:
confirmed that the air filter is completely clean
changed out the gasoline
disabled the low oil kill circuit
removed spark arrestor, which was not obstructed
tried running with the gas cap off (to test for vacuum problem)
disassembled and cleaned the carburetor/jets, which was pristine; no gunk

Might anyone have any other suggestions?
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Old 05-10-2019, 05:01 PM Thread Starter
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I've also changed out spark plug
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Old 05-10-2019, 05:56 PM
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Welcome to the forum! You've checked a bunch of stuff, which is great info, but have you tried just the basics?

- Does adding choke make it better, or worse?
- Have you checked for spark, by laying the spark plug against the engine block (cooling fins, etc), and watching for a bright blue spark while pulling the cord?
- Will it run using starting fluid, carb cleaner, or splashing a little gas into the intake? With the air filter removed, of course.
- Have you checked compression?

Your carb work *should* make sure you're getting a proper fuel mix. But maybe you have a clogged fuel filter, or defective shutoff valve, etc. So giving it a definite fuel supply by spraying/pouring a little into the intake, is a good idea. That way you know you have fuel. Then you still just need compression and spark, to complete the required combo.

Are you getting good fuel flow to the carb, if you briefly pull the fuel line off the carb?
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Old 05-10-2019, 07:50 PM Thread Starter
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I'm sorry for leaving out the following info:

- The generator only runs on full choke. Moving the choke out of full choke kills the engine immediately.
- I have checked the spark plug and it has good spark.
- The carburetor does indeed have great flow. Even before disassembling it to clean, I unscrewed the bowl plug and watched a solid stream flow out continuously.
- The shutoff valve works correctly; I used it with the hose pulled off the carb for draining old gas. Closed and open both work correctly.

- I have not tried starting fluid. I will try that.
- I have also not checked for compression. I need to lookup how to do that.

Thank you, RedOctobyr, for the input.
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Old 05-11-2019, 11:51 AM Thread Starter
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A bit more info:

The generator has under 40 hours on it (it just looks bad because it sits outside under a shed).

Whenever I run it, to turn it off I disconnect any load and then turn gas shutoff to OFF and let it burn all the gas out of the carburetor.

I've read about compression-checking and found that I need to get a tool to do that. I'll do so on my next trip to harbor freight.

I also will need to get some starting fluid, as I have none on hand.

I will update, and I appreciate your input.
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Old 05-11-2019, 03:50 PM
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Sounds like you have an issue with the main passage in the carb. & the direct passage (choke) is starting to clog as well. Probably time for a new carb. they can be found on ebay & amazon for cheap just might have to get the part number off the old carb. may even have to do some part number cross referencing...
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Old 05-11-2019, 04:56 PM
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You can use just a little splash of gas, or a spray of carb cleaner, or some other flammable spray, if you don't have starting fluid handy. I think some people have used WD40, but I've never tried that, not sure how flammable it is now.

If adding a separate fuel source (like starting fluid) lets it run briefly, that's great, then we know you have a fuel problem. But it could still be something else, like low compression, some sort of a valve problem, possibly something less-likely such as an ignition timing issue, etc.

As Matt1097 said, I would make sure that the main jet is clear, and isn't partially restricted due to corrosion, a piece of grit, etc. You can do things like running a copper wire strand through the jet to help make sure there't nothing blocking it.

If the testing points to a fuel problem, and cleaning doesn't help, then a new carb is definitely worth considering, if you can find one at a good price.
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Old 05-11-2019, 08:10 PM
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Yes you are right, cheapest thing would probably be the compression tester from HF, I have been around alot of high performance small engines & also seen alot of cheap chinese engines, he said when it was running it would only run on choke which is why I was leaning towards carb. issue.
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Old 05-12-2019, 07:57 AM
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Compression tests are good, but unless the number is *really* low, it doesn't necessarily indicate mechanical problems with the engine. Most engines have a compression-release, to make them easier to pull-start. This artificially lowers the compression reading at low RPM.

So even though an engine might make, say, 100 psi while at operating speed, you might only measure 50 psi at pull-start speeds, since the compression release will be engaged. Therefore the low reading doesn't necessarily mean you have a problem. I have an engine that make around 90 psi using the electric starter, but only measures about 40 psi will the pull-starter. The valves are adjusted correctly, the cylinder bore is good, and it makes good power, so I'm comfortable that it's "healthy".

Do you feel "normal" resistance on the pull cord? And distinct resistance when you get to the compression stroke? A compression tester is a good tool to have around, but I don't want to accidentally make it sound like some $20 item is required to check out your engine. Starting fluid, or a splash of gas, is a cheaper place to start. Especially if this problem suddenly appeared out of the blue, which would seem unlikely to be compression-related (unless like a valve is suddenly sticking).

If you have feeler gauges, you could remove the valve cover and check/set the valve clearances.
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Old 05-16-2019, 12:27 PM
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Based on what I've seen here it's not getting enough fuel. Try removing the carb bowl then with a small screwdriver remove the jet (up inside the carb). Use carb cleaner (soak it for awhile) and blow it out good and make sure you can see daylight through it. Re install and test run.
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