My mower has a 6.5 Intek motor, model 120602, type 0164-E1. The last time I tried to mow, it ran fine for the first 30 minutes or so. Then it seemed to lose a little power, and I noted that the self-propelled belt had slipped such that it was engaged full time. I stopped the mower to correct the problem. It started back up and ran for another few minutes, but lost power again and finally just died. When I tried to start it up again, I couldn't get it to start.

It is getting spark, and will fire and seem like it's going to run, but it dies after a few seconds. In troubleshooting I did find that the spark seemed a little weak, so I put in a new plug. The plug does fire better than the old one, but I still won't keep running. I will admit that I haven't gapped the new plug (can't find my gap tool for some reason) but the new one looks to be gapped very close to my old one, which I had recently gapped at .020.

Prior to this problem, I have had hot-start issues. If I had to stop the mower to put gas in it, restarting would take a lot of effort. (Possibly 30-40 pulls.) In these cases I noticed that gas would sometimes come out of the air cleaner. I could hear sizzling behind the air cleaner, so I'm assuming it was boiling the fuel in the bowl, which keeps letting the float down, thus allowing more fuel to flow into the bowl. The flow issue only happened when it got good and hot. If I walked away for 15-20 minutes and let it cool off, it started right up (2nd or 3rd pull).

I should note that I recently got the mower back from the in-laws, where it had been stored outside for at least a year. There was water in the oil (very light grey thin milkshake for oil), and the tank was leaking at the seams. I put a new tank on it, a new air filter, and changed the oil. Since then it's run pretty well, other than the hot start problems and a little surging). I probably ran it for 10-12 hours total before this latest issue started. I think it's not getting enough fuel, but I'd think if it was a gummed up carb, I would have had this problem from the beginning.

Sorry for the book. I just wanted to make sure I gave all the details. Thanks for the help!

Well, I've dug further into it and realized the thing has no compression. With the plug still fully seated, I can turn the motor over by hand, and can hear a woosh sound as it turns over. I can see black around the mating surface between the head and the cylinder assembly.

Soooo..... How hard is a head gasket on a Briggs 6.5 Intek? I've done the headgasket on my Geo Storm before (1.6L Isuzu 4-cyl). It can't be any harder than that was. :) Any gotchas I should watch for? Can I get away with just replacing the gasket, or should I consider resurfacing the head?

Thanks for the help folks.

Replacing a blown head gasket on this engine is fairly straight forward, and is not difficult. you will need to reset the valve lash when it is reassembled but other then that, there is nothing real special about it. You may also want to clean out your carburetor and replace the float needle and seat.

Thanks 30year. It was pretty straight forward. It's back up and running now - stronger than it has in a while. I think the compression had been low for a while, because it handles thick grass a lot better now. On car head gaskets, some people suggest retorquing the head bolts after a week or so - is that necessary with one of these motors?

I do still have the hot-start problem though. (Although it has improved some.) I guess the next step is to replace the float, needle, and seat. I'm tempted to put a cut-off valve in the fuel line, because I can definitely hear the fuel boiling in the bowl when it's hot. There is a barrier between the head and the carb, I'm assuming to act as a heat shield. It doesn't seem to be doing a very good job. I figure if I put a cut-off in the line, at least I can keep it from draining gas out of the tank until it cools down. :)