I have a Craftsman lawn tractor with a 17 hp OHV Briggs model #311707-0132-E1. I seems to run fine until I start mowing. The added pressure on the engine from the cutting is creating a huge cloud of white smoke. It stops as soon as I stop the blades and put it in neutral. I assume oil is getting into the combustion chamber.

Is this repairable or do I need to replace the engine?

Thanks

707 in the model number reminds me of something...

WITH a ohv engine... or any engine, you could have a bad breather (lets crank pressure and fumes out, but not the oil) to too much oil or gas in the oil...

OR with ohv engines only... a blown head gasket (usually blows in the thin spot) overpressurizes the crankcase and out the breather the oil goes.

I changed the head gasket. There was an area between the cylinder and the push rod area that was worn ( blown ) through. I put it back together and it won't start. The only thing I wasn't sure of was which push rod went on top and bottom. One has a ball end and the other was flatter. I could not find a clear diagram online. Could you tell me which is the upper and lower? If they are swapped, would they be damaged? Thanks.

Exhaust steel, intake aluminum...
I'm not 100% on damage being done... or not since some use aluminum for both.

http://faqs.custhelp.com/cgi-bin/faq...ted=1101860144

Here's a page on adjusting them.

They were swapped. I changed them back and checked the valve clearance. The clearance needed to be tightened up a little, probably due to the new gasket. There seemed to be some additional wearing on the intake valve head ( slight rolled edges ) which may have been caused by the swapped push rods. The engine started on the first crank! I only ran it for about 15 minutes. I won't get to mow the lawn until this weekend. I hope I won't have to contact you again but if I do I'm sure the information I get back will be right on! Thanks for your help!

Well, things just got worse. I ran the mower for about a half an hour last night and noticed it was overheating. I let it cool down, changed the oil, checked the breather tube and it seemed clear. I ran it for another minute or so and crack... it stopped. I checked the piston and it moved with a push of a screw driver. The flywheel turns about 3/4 by hand but not all the way around. Is it worth it to try and repair or get a new shortblock or a whole engine? Do many of the Briggs vertical lawn tractor engines have the same footprint/mounting hole location? This may allow me to shop around for a different engine. Thanks!

Ouch... it sounds like the conrod (and if it was run low before? ) it sounds more like it even more... (as less oil to lube it, causes it to scar and heat up)

And yes all the footprints will be the same... as a example I just swapped a wore out 12hp I/C single cylinder out for a 18hp apposed twin cylinder (with cast iron bores)

The wiring might not match up though (which was the case of mine, had to swap the wiring)


I'd take the engine off and out, and open it up to see the extent of damage first though.

There was the correct amount of oil when it overheated. It could have been a bit old so maybe the viscosity broke down quickly. Before I bother opening it up, I would like to determine the cause of overheating. I don't want to repair it and have the same problem. Could the timing been off after changing the head gasket?

No, I've seen them with very bad timing and never overheat... (rockers so out of adjustment, you had to turn the engine by hand past the compression stroke to start it)

The oil isn't the problem... as long as its in the bottle, its good for years on end.
Now if the shroud, etc... was off, or fins clogged, yes that will cause it.
But how do you know it overheated? (without basically taking its temp... lol)

It was so hot that the protective black plastic cover around the wires started melting and the oil dipstick tube warped. When I removed the dipstick it smelled like burnt oil. I let it cool down for close to an hour and drained the oil back into the plastic bottle and it was hot to carry. The shroud was on and the fins were clear. Could it have been running too lean? Thanks.

Ouch...
Yes it could have been running lean... but that is more likely if the carb was fiddled with.

The plug was on the light side. It's possible that the idle mixture knob got turned when I had it apart to get at the head. Also, there was some aluminum chips in the oil when I changed it. Do you still think it would be worth it for me to replace the connecting rod or should I get a new short block?

Well if the block itself was not damaged (maybe a scratch here and there you can let slide) then yes a new conrod.

Well, I opened it up and sure enough the con rod was shattered where it would connect to the crank. But unfortunately, so was the case... the area that holds the camshaft in place was broken on both sides of the case. I wonder if it was the result of having the push rods swapped? I guess my only option now is a new short block. Do you agree?

No, that shouldn't have happened from the pushrods.. and yes a new short block is in order... :(

I installed the shortblock. When I try and start the engine, it seems there is too much compression. Without the plug in, it turns freely. With the plug in, it won't crank past one full turn. Before I try a stronger battery, is there anything I may have overlooked? I checked the valve adjustment at 1/4 past TDC.

I jumped the battery and was able to get it to turn over. Now I have fuel adjustments to make. It backfires and won't stay running. The plug is soaked and fuel is getting spit back into the airfilter when it backfires. I have not been able to find any information on carberator adjustments for carbs with the fuel solenoid and an Idle mixture with a cap-limiter. Do you have any suggestions?

I'm sue the cam and cank wee lined up? Flywheel toqued to spec?

If it has a fuel solenoid, thee is no adjustment... just a baely adjustable idle...

Wied... the lettes ae missing

I assume they are lined up. It was a brand new shortblock. I used a brand new key for the flywheel. I will check the torque. I could not find information on the mixture idle adjustment. With the cap limiter, it only turns 1/2 turn to the right or left.