By JOHN DAVIS Reeord-Eagle staff writerTRAVERSE CITY — Traverse City’s Leon McMahon captured the pole position for the traverse City 250 snowmobile, race for the second year in a row Saturday, when he turned a' lour-lap average speed of 77.272 miles per hour.His speed, like that of the entire field for this year’s race, was off the record-setting pace of a year ago, .When he established a new track record with a speed of 78.045 mph.McMahon, using the same 650cc Yamaha engine he set the record with last year, but with a different chassis, captured the pole position with his first run Saturday morning,Until that clocking, Gene Denman Jr. of Acme had turned the best speed of 76.654 mph in the first time trials run made for the seventh annual race, Monday morning. Denman’s time held up for the second-place position.McMahon, who won $500 for being the top qualifier; had to switch to the 650cc engine after blowing up a 433’ liquid-cooled motor in his first run Monday.‘‘That was the same machine I used to qualify for (Satur-day's) Thunder Bay 250,” said McMahon. “After I blew it up,: I changed to the other, engine. It made quite a little package .. and it worked.” ...- Replacement parts for the original engine didn’t arrive until Friday, too late for MeMahon .to compete in the TB 250, which .was won by Dave Yarhouse of Evart.■ / Time trials tor Saturday’s TC 250, showed an increase in the number of sleds attempting to qualify, as. 136 made runs during the week, compared to 125 last year. Qualifying runs totaled 3*22. .Although the number of sleds attempting runs was higher.250 pole againSpeeds were somewhat disappointing, as officials, had expected them to reach the 80 mph barrier. The cut-off speed was 69.898 mph, while last year’s was 70.112.Slower speeds were due partially to. the closeness of the race dates for the Thunder Bay and Traverse City races (one week apart), but- also were effected by a bumpy track”, according to McMahon.“I don’t know what it was, but the track just seemed to get bumpy sooner this year,” he said.McMahon appeared to be turning in another strong time trials run, after capturing, the pole Saturday, when his machine ran out of gas on the fourth lap. He explained that he hadn’t noticed that gas ran out of the sled when he tipped it on its side to make some adjustments in the pits.“That’s the way it goes in racing,” he said. But I’m really excited about this year’s race. The chassis I have now is lighter than last year’s and seems to be holding up real well through .time trials sotar. I think I’ll have a good chance of staying in this year and maybe, winning it.”Numerous mechanical problems and adjustments resulted in a 20th place finish for McMahon in the 1975 race.Rounding out the top five spots behind Denman, who is riding a Yamaha 433, are-former winner George Patuilo, of Caro,• on a.Polaris 446 (74.453 mph), Gerry Wagar, of Petoskey, on a Yamaha 440 (74.187 mph) and Yarhouse on an Arctic Cat 650 (74.020 mph).Last year's winner, Jim Wohlfiel of Pontiac, is in 23rd position, with a John Deere, the only one in the field.The 50-sled field for the race; which is scheduled to start at ,10 a.m. Saturday, included 18 Yamahas, seven Polarisis. 14 Artie Cats, three Mercurys, one Ski-roule, three Ski-doos, one Sno-jet and two Ruops.