For all you boys that feel under-powered

[Porkchunker]

What you have encountered is very common with the plates that bolt on the top or the ends of the anti-ventilation plate (like you've done). The problem is so common that most motor manufacturers will void the warranty on the lower unit.

That is why the plates that bolt to the bottom of the anti-ventilation plate (like the Cobra plates I have) are the way to go. I specifically sought out the bottom mount and only found two manufacturers, Cobra and Permatrim. At the time, Permatrims were much more expensive, so I went with Cobra. If I had the money at the time, I would have gone with larger tabs. But I didn't, so the Cobra plates are what I installed and couldn't be happier.

Dave

 

[DaleH]

I also think those plastic hydrofoil tabs are WIDER than Cobras and Permatrims, thus making them more susceptible to strikes of crab & lobster pot buoys.

If fact (although I have nothing to back it up) I believe the vent plates with foils on them are more broken by lower unit impact strikes from things in the water.

 

[evinrudejim]

Your comments are all pertinent, interesting and intelligent. But it seems like you all missed my point... ass-heaviness is a result of too much weight on the stern of the boat. I jetted my 4-stroke kicker (about 90lb) and then the F200. Lost close to 200 lb.s (with the E TEC) off the the stern. STILL, with a full fuel tank of 150 gallons it's STILL a bit ass heavy. DESIGN FLAW. Tabs alone will NEVER totally correct this problem. At best, they will lift the stern some; but you loose out on the INCREASED DRAG which will absolutely limit your top speed.
IMO you are barkin' up the wrong tree with the 4-strokes...too much beef and too little torque.

 

[greatcir]

Some of us are locked into the engine we married so we need to make the ass heavy relationship work. With my 150 Yammi 4 on my 2120 I could not get the nose down. Putting 100 pounds of lead in the anchor locker brought it down about 4 degrees. More weight there did not help but I was in the 5,700 RPM range with my 14.25X16 ss.

Next I called Yammi about drilling holes to mount plates. They said my warranty would be in full force except for repairing any damage to the cavitation plate. So I drilled four holes and mounted a StringRay. I could feel the extra aft lift but had to constantly retrim tabs & engine. Nose angle unchanged & on plane easier & same speed but always fooling with trim. WOT meant big progressive porpoising unless the tabs were way down.

I took off the StingRay (before I saw the broken cavitation plate above thank goodness) and mounted a ss Cobra plate. Now we are getting somewhere. Good lift and good on plane ....lost some top end speed & RPM but once set on a good cruise it stayed in place like it should. And the Cobra is mounted under the cavitation plate so its pushing up is good on the entire plate. Now to avoid porposing just need a few lights down on the Lencos. Took the 100 pounds of lead out of the anchor locker and not much difference except need another light down on the Lenco indicators to not get porpoising at WOT.

Last Sunday I went out for test run #2 and to see some eagle nests which meant getting in some really skinny water up a long wide slough and, yep, I ran hard aground. Water was streaming out the pee hole in the black water mixed with weeds so I trimmed up the max & powered out till I found 3 feet of water. Cleaned the weeds off the prop and scrubbed the water intake holes and inspected the motor, prop and Cobra. Looked like they were all still new.

Today I looked at Piranha props and ProPlus props (West Marine). Hard to tell which would be a better spare prop for me and give me another test point so I ordered the ProPlus because with the 14.5 diameter I can vary the pitch inch by inch from 15 to 21 without removing the prop (if the video is correct). Will post more on this later but I'm satisfactory for now - not great - but okay. Hope I can get a bit more nose down and less WOT porpoising with new prop, but life is an experiment.

Thus for quiet smoke free rides I'm satisfied with my butt heavy partner. And I still have a 90 HP 2 stroke for sale on a boat that people will not even come see because it is a 2 - not an issue of price, just public perception. So when I eventually sell, thank goodness it will be a 4.

 

[evinrudejim]

If that carburated 2-stroke was on a BW Montauk 17 it would sell in a NY minute...You are right: NOBODY WANTS A CARBURATED 2-STROKE. (Well, actually there is a good market for them in Mexico...) My new 2007
E TEC is a Calif. 3-Star rated motor (Ultra Low emissions); the F series Yamahas are all dirtier 2-Star (Very Low emissions) motors. The E TEC BURNS 30-40 PERCENT LESS GAS AND OIL THAN A CARBURATED 2-STROKE. And, in doing so, ALSO beats 4-strokes in EVERY CATEGORY!
The Yamahas DO NOT PUT OUT THEIR RATED HORSEPOWER- Yamaha will admit this if you ask. They also lack the inherent torque of a comparable two-stroke. Add in the extra weight, complexity and the astronomical maintenence required for a 4-stroke and the decision to go with the E TEC was a no-brainer. I figure maintenence on an F series Yam will be about $2000 in a 3 year period (100 hr.s per yr. avg use). Since the E Tec only requires routine Maintenence every 300 hr.s - at a cost of only $500, I am money ahead with the E TEC. I'll spend the savings on gas.

 

[Parker23]

Hope so lets see in a few years if it is true.