Poulan 25HP Intek - Runs Rich under load

15 years ago

Hello,

If anyone can steer me in the right direction, I would be very grateful.

I have a 2001-02 Poulan 48" deck mower with electric deck engagment. The 25HP Intek engine has the electric fuel bowl.

The proplem is:

Runs fine at idle and at high speed, until you engage the mower deck. Then it starts flooding, blowing black smoke from the exhaust. Seems to run rich.Cut the mower and it clears up immediately. I have sprayed carb cleaner around all of the gasket areas looking for a leak and found nothing. The carb does not look like it has a adjustment screw, unless it is hidden very well. Some days it runs ok, other days(most) it runs bad under a load. Even at idle it smells like it could stand to run a little leaner on fuel. When it is warm it sometimes has a rotating surge.

Thanks,

Ed Benesch

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Comments (6)

bill_kapaun
15 years ago
Does it seem real low on power?
IF so, I'd suspect one cylinder isn't firing for some reason.
You might examine/replace the spark plugs. A weak plug might fire OK until the throttle opens up and fills the cylinder more with air/fuel, raising compression.
IF the problem continues, I'd alternately remove one plug wire (ground it) and see if it's isolated to one cylinder.
IF so, I'd pull the valve cover on that side and see if the valves are functioning properly. You could also start it for a moment and see if you have compression/combustion gases leaking.
walt2002
15 years ago
Like Bill said.

Walt Conner
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edbenesch
Original Author
15 years ago
Thank You for the post, I will try your suggestions and report back........

Ed
edbenesch
Original Author
15 years ago
Hello Bill & Walt,

I tried what you recommended, after installing new plugs, the exhaust smelled like it was burning clean so I took it out for a test run, engaged the deck and it started to load-up with fuel and lose power again, after I dis-engaged the deck, the fuel mixture smelled rich again. I took the valve covers off, checked the operation of the valves, and checked that the pistons were moving, checked to see that the choke was closing all of the way, I have been running fresh premium fuel. When I took out the old plugs, one was wet, one was dry, both were black. If yu ahve any other ideas, I'd love to try them. And thanks for the help you already provided.

Ed
bill_kapaun
15 years ago
One idea would be to read my post about "IF the problem continues..."
mownie
15 years ago
I doubt that the following has any bearing on your current problem, but I noticed you mentioned that you "run premium fuel". I presume you are using "the higher octane rating". The HIGHER the octane rating.........the SLOWER the fuel burns. High octane rated fuel is made for engines with high compression ratios (to minimize spontaneous ignition/detonation). Nearly ALL gasoline fueled engines manufactured after the early to mid 1980's are designed to use regular grade of pump gas (87 octane). When you use "premium grade" gasoline in a low compression engine you are accomplishing 2 things for sure. #1..You are paying more money for a product that you will not be able to realize it's intended benefits (because the engine has too little a compression ratio). #2...You automatically ensure that more unburned fuel will be present in the exhaust stream (because the high octane rated fuel cannot burn completely in the power stroke portion of the operating cycle in a low compression engine. I realize that a lot of folks think that you get more power by using "premium grade gas", and they get a "feel good" in doing so. The truth about premium gas yielding more power only occurs if the engine in question actually has a high enough compression ratio to REQUIRE high octane fuel.

Poulan 25HP Intek - Runs Rich under load

Comments (6)

bill_kapaun

walt2002

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edbenesch
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Poulan 25HP Intek - Runs Rich under load

Comments (6)

bill_kapaun

walt2002

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edbeneschOriginal Author

edbeneschOriginal Author

bill_kapaun

mownie

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