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I have a Snapper mower with a Briggs motor (121Q 02 0028 F1) 850 professional series motor. Withen one year I blew a head gasket on the motor. I took it into my Snapper dealer and had the head gasket replaced under factory warranty. Now when I start up the mower I get White smoke for about 4-5 minutes. Once it's warmed up the smoke dissipates. I'm I looking at another blown head gasket or is there some permanent damage that occurred to the rings/cylinder?

Check the oil level and make sure it isn't overfilled, and also make sure it doesn't smell like gas.

I have a 25hp briggs V twin, that smokes a lot (white smoke). Is there any way to be sure it's the rings, and not something else before I tare into it? Oil level is good. Maybe a little low. I have to add oil regularly.

White smoke often indicates blown head gasket. Some say you can remove the valve cover and look down pushrod gallery while the engine is running and be able to see head gasket leakage. I have never tried that. Be aware that a little oil may leak, be blown out, with valve cover removed.

Walt Conner

hrdman2luv said:

I have a 25hp briggs V twin, that smokes a lot (white smoke). Is there any way to be sure it's the rings, and not something else before I tare into it? Oil level is good. Maybe a little low. I have to add oil regularly.

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You've been on this site for more than 3 years, ... you should know better than to "hijack" someone else's thread, why didn't you just start a new thread and NOT create confusion, even though YOUR problem is similar, it's a chaotic situation trying to address 2 different people in a single thread. just sayin, it's easier to answer in separate threads ! .. :thumbsup:

The usual trick for confirming a head gasket is to run the engine for 5 minutes then turn it off, wail a minute then open the dip stick.
If you get smoke coming out the head gasket is gone.
The other tell tail is a hesistation , usually acompanied by either black or white smoke when the throttle is opened wide.
The sort of thing that happens if you tromp on the drive pedal & engage the pto at the same time..
If the gasket is leaking externally you will get a roar when the throttle opens initally the it will drop off.

No real neon sign, just lots of small arrows all pointing in the same direction.

Boobala said:

You've been on this site for more than 3 years, ... you should know better than to "hijack" someone else's thread, why didn't you just start a new thread and NOT create confusion, even though YOUR problem is similar, it's a chaotic situation trying to address 2 different people in a single thread. just sayin, it's easier to answer in separate threads ! .. :thumbsup:

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Sorry about that. I thought the topics and engines were similar enough that the OP and I could take advantage of the same diagnosis.

hrdman2luv said:

Sorry about that. I thought the topics and engines were similar enough that the OP and I could take advantage of the same diagnosis.

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NO BIG DEAL, and I'm NOT trying to be a wisearse, it's just easier on ALL concerned, if each thread has it's own answer, but you can always reference to a posting in another's thread.

Doing a compression leak down test can answer both threads. And while the suspect cylinder is pressurized listen to where the air is leaking to. With the dipstick off if you hear air leaking into the engine its the rings. If its leaking around the head-head gasket. Or take valve cover off and see if its the valve seals. It could also be the crankcase breather.