Quote:
Originally Posted by DoozleD
5500 at wot=37 kts...likes to run around 3600, to 4000rpm's for cruising, its hard to get it to stay at 3500rpm?..it wants to go to 4000,or 3200?...might screw around with props..4000=about 22 to 25 kts?..I think..cant remember
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In my humble opinion -
If you are considering a light weight, lower HP motor for your 20 Seacraft in the 90-115 range - The E-tec's seem have a slightly different torque profile.
The 90's have a very flat trajectory across the rpm range. They pull pretty steady from about 3200 up to WOT. They are happy to "tractor" along at 3400 all day.
The 115's have a "Crown" in the torque trajectory where they want to surge at about 4,150 due to porting and the adjustable expansion chamber. I'm not sure if they are "weak" below the 4000 mark or if the "surge" above that point just makes them feel a little slugish below 4000. They love 4150 and "spooled up" they yodel!
My 90 is a 20" 2-1 gear and my 115's are a 25" 2.25-1 gear so there may be some slight difference between relative gearing and props. My 115 preformance stats are very similar to yours Doozle, but I can only get to 34 MPH and not Knots with that "Toad" 25 Bert.
As you say, you might be able to reduce the "surge" with some prop adjustment. I have a Powertec 13-3/4 X 14 on the 90 and Merc Inertia's 14 X 14 with BRP hubs on the 115's. Both good crusing props. Gillie approved them.
If your boat is outside, store it with the engine in the down postion. The only problem they seem to have other than the typical contaminated fuel is rain water leaking in the cowling in the up position and getting in the EEM unit. I think they added an additional deflector shield on the new motors along with grease fittings for the expansion chamber so they can give it a squirt at your 3 year service interval. Get out there and use that boat man, I'll be snowing again up there in another 3 weeks wouldn't it?