Briggs 30hp professional bogs down

tony2

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Hello all and thanks in advance for any help. I have a brigs and straton 30 hp professional that bogs down in tall grass. When mower was brand new it ran fine for about a week , then the issue started. Mower is now five years.
over the years of trying to fix this issue i have replaced stator, voltage regulator, checked valves, plugs , run non ethanol gas, checked clutch , wiring, changed belts checked blade housing bearings etc. i have been told that the engine i was sold on the unit is commercial but in actuality it is not. do not know if this is true but guy who told me was a mower mechanic at a high end shop. still, its a 30 hp motor and should cut 12 inch grass. any ideas on what the issue might be ? any suggestions are much appreciated
 

bertsmobile1

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Had a mower like this come into the shop, just after I started, tried all sorts of things hen checked the engine by removing the plugs on each side.
Would not run on the left alone
Why
Because there was neither a piston nor rod in the left side.
Customer "though" it was a bit short in the "balls" department and they have been using it sans one piston since new for 5 years.
 

tony2

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thanks for the reply bertsmobile1. unfortunately thats one of the many things I've tried in the past. motor runs fine when left or right plug is removed
 

Boobala

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12 inch grass might be the problem, have you tried raising the deck and making 2-3 passes or cutting more often, I assume those blades are sharp, are you mulching ..?? or discharging out the chute ?? Are you using any type of grass collector system ..??

If you get your engine Model, Serial, Family numbers you can call one of the replacement engines supply houses and the can probably give you all the info on your particular engine ... Pro series ( I think ) started 30 HP in 2009, and model numbers were 49M877 .. Commercial was 49M977 and some Pro 30 HP were 49G575 But don't hold me to it.
 
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tony2

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i run high lift blades some and mulch blades other times. no grass collection only straight discharge. the only way i can get it to cut is by making 2/3 passes. if i hit the grass at half speed in one pass height it bogs the mower to the point that it almost stalls out. this mower is all heavy duty commercial 54" outlaw series. blades extremely sharp. I've seen similar mowers with 24hp engines take taller grass with thick wet weeds run full speed without slowing or missing a blade of grass. I'm almost to the point after all this time of replacing with a 870cc kawasaki engine. the only reason i haven't yet is because i can't prove through process of elimination whether is engine or mechanical. just can't find anything on it that looks bad or doesn't work. i only use it on my yard and mower has only 130 hrs on it after 5 years. another reason i haven't swapped engines yet is i can't stand not knowing why this one won't perform.
 

DK35vince

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i run high lift blades some and mulch blades other times. no grass collection only straight discharge. the only way i can get it to cut is by making 2/3 passes. if i hit the grass at half speed in one pass height it bogs the mower to the point that it almost stalls out. this mower is all heavy duty commercial 54" outlaw series. blades extremely sharp. I've seen similar mowers with 24hp engines take taller grass with thick wet weeds run full speed without slowing or missing a blade of grass. I'm almost to the point after all this time of replacing with a 870cc kawasaki engine. the only reason i haven't yet is because i can't prove through process of elimination whether is engine or mechanical. just can't find anything on it that looks bad or doesn't work. i only use it on my yard and mower has only 130 hrs on it after 5 years. another reason i haven't swapped engines yet is i can't stand not knowing why this one won't perform.
Must be some pretty thin grass you have if they are mowing it at those speeds with a finish mower.
The thick grass around here you would need to mow real slow to cut 12" grass with a finish mower of any kind and it would still be a crappy cut. Especially with 24HP it wouldn't happen at much over a crawl.
That's getting into brush mower mowing depth.
 

ILENGINE

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Ran a Turf Tiger II if I remember correctly that belonged to a customer a few months ago. Had the 27 EFI Kohler engine, and I don't remember deck size. Either 54 or 60 I just don't remember. Wouldn't handle 6 inch grass cutting 2.5 inches high, and had to creep to prevent killing the engine. Probably couldn't mow more than about 1 mph.
 

tony2

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did you solve his issue ilengine? if so would you let me know. may be something i haven't tried. as for the 12 inch grass that was a guess. because of my job and the rain patterns around here i generally go a few weeks between grass cutting unless we are having a drought:laughing: i usually cut at 3.25 deck height and grass may only be 8" but regardless same issue. mower just won't do it without 2/3 passes unless like you said 1mph or less
 

ILENGINE

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Tony2 The reason i was repairing this mower was because of intermittent start that came down to a faulty pto switch. In the case of this customers Scag just not enough HP to pull the deck and the hydros. Just too heavy and robbed a lot of power. Engine was running fine.

I suspect it isn't an engine problem, unless you are dropping a cylinder under load which is possible. Not enough fuel to one cylinder under heavy load, or could possibly be loosing spark under full load. Or maybe nothing is wrong at all and it has the same issues of just not enough power to pull itself and keep up with the load of heavy grass.
 

tony2

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thanks for the input ilengine. i have always suspected that might be the case
 
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