Mercury Snowmobiles Discussion Board

Sounds good. Not too many free-airs of any brand will run with a dialed in Kohler in Stock class drag racing.

Thanks for the info. Those numbers look good. Just curios - what do you use for clutches? I like the hex. Other guys have better luck with the Comet. I know Tom Priebe over in Wisconsin runs a Comet on the '75 Merc 440 that they run, and that sled is fast,...... probably faster then my Rupp. Alot d...

Just a quick up date to an old post of mine regarding my 340 f/a engine with the Tipster sheet specs. I am currently racing that engine in my mod stock Rupp F/A chassis. The sled runs good, in spite of the fact that I am still running the complete stock Rupp exhaust system along with 38mm carbs. The...

My '75 Rupp F/A 340 stocker has run a best ET of 7.26 @ 64 mph at the Princeton grass drags here in Minnesota. My 440 Rupp F/A stocker has run a best of ET 7.11 @ 69mph. So yes,.....the ET and top speed you are looking for from your Merc are achievable.

I agree with Joe. Give me a good 'ol Hex clutch any day.

Kerry, I raced against you several times this winter and have alot of respect for you and your sled. Do not abandon your current set-up. You are doing alot of things right or you wouldnt be running so strong. I believe all you need is some fine tuning. I know I must get faster by next winter if I ex...

Although not a Mercury, my stock Kohler RS powered Rupp F/A 440 runs 74mph in 500ft (electronic speed trap) and my 340 Rupp F/A runs 71-72mph in the same 500 ft.

For Sale- ' 74 Merc Twister open mod race chassis. This sled would be good for speed runs or drags. This is a true vintage mod sled, probablely built back in the mid '80s. Sled features Wahl gas tank and skis, ' 75 Z Cat suspension/w custom cleated track made from Rupp Magnum bands. Chassis only, no...

The compression on a 340 RS will typically be 150 with a good engine. They will still start/run decent with as little as 130-135,...but the engine will start to get hard to start if you drop down to 125.

The idle screws are the large screws with the heavy springs on the sides of the carbs. Start by turning them all the way in, then turning them out 3 turns and see how it idles. Turning the screws clockwise will raise/increase the idle speed, turning them out will decrease idle speed.

Scott, thanks for the reply. I will give a report on how the performance changes, whether good or bad, with the new porting after testing the sled on the electronic timer next winter. I am not that concerned if some low and mid range performance is lost, as the sled will only be drag raced. The only...

I already asked this question some time ago and no one replied, so I thought I would try again. Has anyone out there ever tried the SuperMod porting specs for the K3402rs engine as found in the TwisterTipster bulletin? How much of a performance gain was found? I had my cylinders cut to these specs l...

Thanks Scott!

Can someone please tell me what the stock gearing is on a ' 76 440 Sno-Twister? Thanks in advance.

Wow. It seems amazing not ONE of you Merc enthusiast has ever tried the mod porting specs outlined in the Twister Tipster bulletins. Amazing.