Promax 150 - Mods worked

[promax150]

It worked. Some performance help for a promax 150. I asked the guys on this board about getting a wee bit more by changing the tuner. The stock one is very long - nearly as long as the midsection. The consensus was that it would help, a little but not a lot. After a call to Ric at RicRacers, he sent a Bob's Tuner, all the gaskets and suggested that I replace the stock cylinder head gaskets with a thinner version to bump the compression a little. He had three versions of the gasket stock, thinner and thinner still. I chose the middle one.

This is what it produced, about 400 more rpm. I hit 6500 with my favorite prop, prior to I saw 6100 tops.

I don't know if the tuner did this or the bump in compression. I have'nt done a compression check to see how much of a bump I got from the stock 135psi. Nonetheless it helped.

I did keep the liner in it (it's on a fishin boat) to keep the sound down. And yes you can get a bobs in a liner if you grab a grinder, though I bet a 200 or 225 stock liner would do the same trick without grinding. After doing it twice because of a water leak, I would like to meet the guy how designed the two piece exhaust plate. Seems like a terrific place to produce water leaks. There has got be a better way.

Thanks to Tony Brucato, Ric and US1 - They all helped.