Mower overhual, engine rev problem

[HVF]

Hi, I just overhauled my mowers engine (my mowers a Craftsman model #917.374821 with 6.75hp and a "pressurized" oil system) after finding it burning lots of oil. It has been through only 3 seasons and last season it started to burn oil (lots of it) and it backfired every so often. So this season I overhauled it, well sort of, I replaced all the old gaskets including the head gasket but not the cylinder head O-rings.

After I replaced all the gaskets and scraped off the carbon from the cylinder head, I reassembled the mower, I even washed the thing it looks factory new. I soon found out that I could no tighten any of the bolt to their specified foot pounds of torque, the flange bolts could only be tightened to about 15-20 fpt far from the specified 115-120fpt printed on the card that the new gaskets came in. I found this out the first time I striped a tap. The head bolts could only be tightened to about 40fpt, really the only thing that could be tightened to the correct fpt was the fly wheel. I don't know if craftsman screwed up with the instructions or the mower, might be both.

Anyway, I started it up for the 1st time after the overhaul and it revs up then stops for a millisecond then revs up again. It works but lacks power. I think it could be water in the gas, but since the bolt problem and the previous problems (which aren't happening anymore) I am starting to think it may have to do with the cylinder o-rings and it is allowing some pressure to escape into the crank case and because the carb works off vacuum from the crank case it may cause fuel mixture imbalances. But the sound it makes is just unusual to me, so I am going to upload it to the groups file temporarily so you can give it a listen. Please help me find out what's going on. Note: the sound clip is of the highest quality done with a studio quality mike so I can assure you that there are no crapy computer sounds, all of it is from the engine. And after the first 20 seconds or so I pulled the carb manually to full open. (Before that I am not messing with it. That is the rev up and down thing I am talking about) The file will be called "mower.mp3", and will have the caption "HVF mower sound".

Thanks, HVF

[~Roy]

With all those bolts and fasteners stripping their threads, I have to wonder how yu actualy torqed them..When was your torque wrench calibrated, or was it ever calibrated at all since yu got it. They are known to get ouyt of wack or be crazy even when brand new no matter what brand they are......USe it in the worng direction to loosen if it wa not cal'd in that direction or leaving it set on a higher range than thelowest setting when not in use al screws up a break over type torque wrench. For thebending beam type ,well they really need to be cal;'d just the same and are not quite as precise as a break over type but same criteria for use and after and before use applies with the exception of settingonlowest setting when not in use.

Are you sure the head bolts on that engine are supposed to be torqued to 115-120 "foot pound" and not inch pounds?

It sounds more like an impr>>Hi,

============================================== Put some color in your cheeks...garden naked! "The original frugal ponder.."Since my statements are given freely, take em or leave em, I am entitled to my opinion none the less. My opinion and $1 is still only worth $1..... ~~~~ } ~~~~~~ } ~~~~~~~ }

[Oren]

1) Never, ever work on the steering of you truck.

2) Try another torque wrench.

3) What files?

4) Adjust the carb, maybe....

Oren "My doctor says I have a malformed public-duty gland and a natural deficiency in moral fiber, and that I am therefore excused from saving Universes."

[m Ransley]

The quietist mower I never heard.

[~Roy]

============================================== Put some color in your cheeks...garden naked! "The original frugal ponder.."Since my statements are given freely, take em or leave em, I am entitled to my opinion none the less. My opinion and $1 is still only worth $1..... ~~~~ } ~~~~~~ } ~~~~~~~ }

[Tony Hwang]

Hi, There may be a vacuum leak. Liberally spray WD40 around gaskets, where suspicious. If rpm settles down, there is the leak.

[Oren]

Sounds to me like it is starving for the right fuel/air mixture.

Oren

"My doctor says I have a malformed public-duty gland and a natural deficiency in moral fiber, and that I am therefore excused from saving Universes."

[John Lawrence]

[Robert Barr]

These values are radically beyond anything your aluminum engine block threads could withstand. I'd bet it's calling for inch-pounds of torque, not foot pounds. Divide by twelve.