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Figured out why gen wasn't running great

tealboy
Explorer
Explorer
Some may recall, I posted about my ef2800i having a slight surge, not bad but clearly not right. Played with sea foam, no improvement whatsoever, then decided to try carb cleaner before ultimately pulling the carb and completely cleaning it. I opened the air cleaner and was surprised to find the old foam air filter had completely discinigrated. There was a small amount of ash like residue in the air box but essentially, gone. Obviously, a small amount of particulate got into the carb to cause the surge. I'm surprised the motor ran as good as it did for 2 nights but I guess little entered the carb. I tried carb spray but it did seem to help,so off it must come this weekend
9 REPLIES 9

Dave_H_M
Explorer
Explorer
teal

I saw something similar on an old briggs and stratton 5hpp flat head that had been setting in an old grainery for eons.

If you put any pressure by touching on the foam element it disintegrated

This one will not be run like that, but who knows?

tealboy
Explorer
Explorer
wnjj wrote:
Actually, not having an air cleaner will likely lean the engine enough to cause a surge. On motorcycles you usually have to increase main jet when you improve airflow. Any chance someone took the filter out and forgot to replace it?


Interesting concept on the surge related to no air filter. Re filter being removed, absolutely no chance. Another wondered if a backfire could have ignited the foam, I see no evidence of that nor do I believe that happened but interesting thought for sure.

My sense is,the gen has been sitting since I purchased it in appx 2005 after losing power for a week due to a hurricane. I ran a Honda eu3000 for those 7 days but it was dad,s rv gen. I loved it but was too pricey and too heavy for portability I wanted, hence the yamaha 2800. In 12'years, I have used it 2-3x for light use and started it 2-3x just to run it pre hurricane season. Prior to this hurricane, it had only 12'hours run time. After Irma, it now has 30 hours. Oil, filter and plug are original. Still cranks on first pull but has slight surge which is what started all of this. Fuel has always been stabilized , carb and tank run dry and a few drops of fogging oil directly into the piston. Besides that, nothing done gen sits in box waiting for a storm. Eventually expect to use for rving but hasn't happened yet

In my opinion, the foam filter is 12 years old, had factory oil on it and just rotted out and dissolved but maybe that isn't possible. When I pulled the old foam filters on my honda 2000s, those filters were still there but they were dry rotted and crumbled like ash when I touched them, that's why I'm assuming the yam dissolved, etc. easy fix, don't wait 12 years to ck your filter and replace it, lol.

Going into the carb today, had to do the same w the hondas a few years ago and they continue to run perfectly.

wnjj
Explorer II
Explorer II
Actually, not having an air cleaner will likely lean the engine enough to cause a surge. On motorcycles you usually have to increase main jet when you improve airflow. Any chance someone took the filter out and forgot to replace it?

theoldwizard1
Explorer
Explorer
Check this video out. 2400 and 2800 are supposed to use the same carburetor.

How to fix a surging Yamaha EF2400iS generator

Some well placed carburetor spray at 7:00 of the video.

wa8yxm
Explorer III
Explorer III
Small amount of ash... Backfire?
Home was where I park it. but alas the.
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after a semi "nicked" it. Still have the radios
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SidecarFlip
Explorer
Explorer
tealboy wrote:
Some may recall, I posted about my ef2800i having a slight surge, not bad but clearly not right. Played with sea foam, no improvement whatsoever, then decided to try carb cleaner before ultimately pulling the carb and completely cleaning it. I opened the air cleaner and was surprised to find the old foam air filter had completely discinigrated. There was a small amount of ash like residue in the air box but essentially, gone. Obviously, a small amount of particulate got into the carb to cause the surge. I'm surprised the motor ran as good as it did for 2 nights but I guess little entered the carb. I tried carb spray but it did seem to help,so off it must come this weekend


Sounds to me like the engine spit back through the carb (they do sometimes) and ignited the foam air filter which burned up in the housing and left some ash in the bottom. Time for a new foam element.
2015 Backpack SS1500
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azrving
Explorer
Explorer
lol well I'll be darn. Piston rings and bore are saying WOW finally some relief. Lol

ScottG
Nomad
Nomad
How strange. Wonder what broke down the element?

Lwiddis
Explorer
Explorer
DISINTEGRATED...Wow!
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