Outdoor Power Equipment and Small Engines - Power Loss

I have 2 8HP Toro riding mowers (mod 57300) One I sold to my neighbor and one that I kept. I rebuilt both carbs last year and my neighbors runs great and mine loses power after 5 or 10 min of running, causing bagger to clog up. Idle is great,Accepts gas incrase very smoothly, no hesitation, did not have the power loss prior to rebuilding carb.New gas filter,air filter,spark plug and oil change. Any help appreciated.

Switch carbs with your neighbor!


Seriously, if the problem occurred right after you went through
the carb, then logic would suggest that is where your problem
lies. Post your engine's model numbers so we know what you
have, and can at least give you a better guess as to the
root of your problem.
Without knowing anything about your engines I would take
a wild guess at an incorrect float height, but that would only be if
you had an adjustable float, which we have no way of knowing.
If they both ran fine before, why did you rebuild the carbs?
Fish

Fish,Neighbor keeps that mower locked in shed otherwise I would have had that sucker by now(just kidding) The mower I sold him ran really bad when I bought it and after rebuilding carb ran great and that is when I sold it to him. The reason I rebuilt mine was that I was jealous of the power he was getting and thought that I could get the same if I rebuilt mine but it went the opposite way,serves me right. Don't have numbers for engine yet everything piled on top of it in shed but I'll get back to you with them. Can't figure why the float would do that since there is no hesitation,no fluttering and accepts the gas perfectly. Thanks Fish

Is the engine actually losing power, or is the blade just going slower? If its just the blade not turning fast enough, you may just need a belt or belt adjustment.

Hi Cheese, Glad to see your still on your toes, you still the man. Definitely engine slowing down. The funny thing about it is that it has to warm up before engaging blade or it will stall, then it runs like a bat out of hecks for about 5 or 10 min before starting it's decline. I kinda thought maybe a gas filter but I tried that before putting it away.
scamper

Cheese, do you think it could be vapor lock in the carburetor?

Hi guy's, Engine is a 8 HP.Briggs & Stratton Mod.#191707 Type5816- 01 Code 84010909
Scamper

Hi Scamper!

mower17 is probably on the right track. It could be "vapor lock" in the tank, since it runs well for 5 or 10 minutes before declining. Does the fuel tank have a thumbscrew vent on top? Is it open? Run it until it begins to lose power, then crack the fuel cap a bit to allow air to enter the tank. If it runs well again, the tank is developing a vacuum.

The problem with it stalling when engaging the blade when cold is probably due to a lean high-speed fuel mixture. Back the screw on the bottom of the bowl out 1/4 turn and see if that solves that problem.

The mower is of an age that it could have points, which may be something to consider. Also do a quick check of your valve
clearances.
Fish

Top of tank has a rubber hose overflow.isn't that the same as crackinkg the lid?

Yes, if the cap is venting properly, but if the vent is clogged it won't work. Cracking it open will eliminate the possibility. Do this, and if it does no better, go with fish's advice. If you do have points, you might want to replace them if it hasn't been done lately. The valve clearances could also cause your problem as mentioned.

Yes, if the cap is venting properly, but if the vent is clogged it won't work. Cracking it open will eliminate the possibility. Do this, and if it does no better, go with fish's advice. If you do have points, you might want to replace them if it hasn't been done lately. (how old is the engine anyway?) If the tank is not developing vacuum, I feel like the next most likely culprit is the valve clearances.