Wow, four divers, 8 tanks & equipment etc. and a heavy boat, that's very impressive for the I-3 90 Terry ! I personally would have thought you would have a hard time getting up on plane but like I said, I have very limited knowledge on the subject, hence my post asking for opinions and advice. I've only had three people once in my 18SF with fuel and fishing equipment and I noticed getting up on plane was not very swift, turning a 13.5"x 17P Power Tip Ballistic on the 98 Yam. 115.
Can you pleas elaborate on what you mean by few "Hot Spots" ?

Sounds like staying on plane at lower speeds is high on your priority list.

I think the only motors your considering that run v6 class props are the merc 115 or 90 with the ct gear case and I think the 115 etec does? Someone else could confirm.

The benefit of this us much more prop choices. I run a large prop on my motor, my boat can stay on plane down to about 14mph. It's a bracketed boat to which most will say that hurts low speed planing

Hit 45 consistently with t top. Without the top I have hit 47 in ideal conditions and wind at my back.

The "only" reason for my emphasis on staying up on plane at lower speeds is in the chop/snot.

I don't think there is another reason.

[QUOTE=sidelock;241201] . . . Can you please elaborate on what you mean by a few "Hot Spots"[QUOTE]

Before the advent of the G2 E-TEC, the exhaust ports on all V-4 & V-6 2 strokes dumped into the V between cylinder banks, creating what could be considered a "hot spot" that required extra cooling, which I suspect is what Terry was referring to. The inline engines and the G2 E-TEC do not have this problem.

Regarding fuel consumption differences between the 90 hp Zuke and E-TEC, I suspect that the Zuke will be 10-15% better at cruise, and the E-TEC will be 25-30% better at low speed (below ~1800 rpm) when it's in the stratified charge mode, so the overall average mpg will be very similar on both. For example, my 150 E-TEC burns 0.5 gph @ 1000 rpm & 5mph (=10 mpg) and gets ~3.8-4.0 mpg at cruise; my overall average when carrying a heavy cruising load (2 big coolers, groceries and gear, extra H20 and gas) is typically about 4.4 mpg. A few years ago I circumnavigated S. Florida via the Okeechobee waterway, Florida Bay and the ICW, running almost 700 miles and burning 158.5 gal of fuel and about 1.5 gal of oil for an average of 4.4 mpg. I've also made the 90 mile run up to Sebastian for CSC gatherings 3 times and I typically burn about 20 gallons each way. Another good resource if you have any questions on the E-TEC is the Owners Forum, which is supported by some very knowledgeable techs.

The other items to consider are maintenance costs and proximity to a good dealer. As Terry says, nobody makes a bad motor these days!

Very impressive numbers ! your input is very much appreciated, thanks. I was under the impression that Terry was talking about the I-3 and hot spots but I could be mistaken.

Yea, Denny knows what I'm talking about. Usually when the V-4 or V-6 2-S engines fail (OMC, Yamaha, or Suzuki) the bottom cylinder, wrist pin, Rod or crank is involved. As it is at lowest cylinder in the group and has gathered the most heat going out the stack. The 3 cylinder 2-S in-line engines (OMC, Yamaha, Suzuki and Mercury) seem to have a better disipation of heat across the block than the V design blocks that dump the exhaust in the center. I understand when they designed the G-2 they looked long and hard at what worked well and used what looks like two in-line blocks. Take a peek inside the coweling of one if you can some time. They are even weirder looking on the inside than the outside, but beauitiful castings and craftsmanship. They got a cool little sticker on them too that you don't see much anymore - it says MADE IN USA, and I'm kinda' partial to this place.

As Terry said, any of your listed motors is a very good motor.

I suspect the low speed plane should not be a problem with the zuke. 2.59 gear ratio should offer plenty of low speed guts. The fact that it can spin so much propeller should offer many prop choices, and a good stern lifter can only help your concern.

Your ballistic funky tip, by the way, is a bow lifter. Changing your prop a semi cleaver style like Yamahas own, even a 4 blade - will give you better overall performance likely lower planing speed. It will also help your hole shot with a load. 17 p with the extra cup, rake, and blade design of your ballistic might be a bit much for the Yammie on the SeaCraft hull.

The prop came with the motor when I bought the boat and I thought about replacing it but I'm playing with the idea of having the transom raised to 25" this spring and I'm undecided whether to repower or get a shaft extension kit for my existing motor. The 98 Yam 115 has been bullet proof thus far and hasn't failed me once however this past summer I noticed it running a little rough and vibrates at idle under load. I took it to Bass Pro and they pulled the carbs, cleaned them and checked the reeds but unfortunately it didn't resolve the issue. It only does it in gear at idle and low rpm. Unfortunately the nearest Yamaha technician that's on the water and can check it under load is 2.5 hours drive and I would have to leave the motor with them for a few days so I would have to make two trips.

I repowered my 1975 18' SC last summer with a Suzuki DF90 and couldn't be happier. With the factory stainless prop (14x16) it planes at about 12-13 mph, which, for me, is 3500 rpm. It tops out at around 35. I think it has more than enough mid range torque, which comes in handy running a sloppy inlet. I struggle to stuff five gallons of gas into the tank after a day of fishing. I think it's a great motor.