Bill,
I've done both. I added Bennett tabs first, as part of my V-8 repower project. Drawbacks: Expensive, required transom reinforcement, electrical wiring. And yes I did remove some of the above floor flotation to make additional room.
Positives: Allows for helm adjustment/control, or even optional automatic trimming. Trim tabs also allow independent Port to Starboard load balancing, permit sligthly lower docking speeds with added drag, better hole shots, and ability to adjust planning and wake width speeds under 16 - 18 mph when dragging wake boarders. I can also bring any tendency to porpoise under control by trimming the bow down.
The cavitation plate-mounted foil was added later, (do this first!) I think it helps on hole shots and in preventing prop blow out on medium-to-high speed sharp turns. I do this a lot when a skier goes down and I want to get back to them in a hurry to "protect" them from other traffic. I used a Sting-Ray and am happy with it. One note: If you have a tight 20-ft garage it does take up an extra inch or two in storage length, so measure twice before you cut or drill.
AS far as drilling holes goes, well yes that is a part of the installation, but I consider each a functional, life-long addition.
Lee
________________________________________
From: omc-boats-bounces@... [omc-boats-bounces@...e.com] On Behalf Of BLDFW [bldfw@...]
Sent: Sunday, August 09, 2009 11:22 AM
To: Evinrude & Johnson Boats of the 1960's and 70's
Subject: Re: [OMC-Boats] 2nd Shakedown Cruise
Thanks for the feedback.
I was just on the iBoats site reading (the debate) about hydrofoils -vs- trim tabs. Seems a 50/50 split on the topic with a lot of emotional investment in either method. What I did notice is that it seems most boats referenced are 19' types.
At the risk of opening a debate on this site, anyone care to share their experiences about which path to go down. I could do either but have the same concerns everyone else has...to drill or not to drill....and that can apply to either the outdrive or the transom.
Do Evinrudes have sufficient transom access (one side of mine has a large block of foam) and thickness to even mount trim tabs?
Bill
Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive
http://www.photobucket.com/evinrude_explorer
--- On Sun, 8/9/09, Lee Shuster (lib1) <lib1@...> wrote:
From: Lee Shuster (lib1) <lib1@...>
Subject: Re: [OMC-Boats] 2nd Shakedown Cruise
To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...mate.com>
Date: Sunday, August 9, 2009, 10:26 AM
What fun would old vehicles be if we weren't challenged with solving electrical and fuel delivery glitches?
1) Scott is right-on. Our OMC hull designs are prone to porpoising and "rougher" riding, due to rather shallow center-keel deadrise. His approach with the ventilation/cavitation plate mounted foil is sound. You can also add adjustable trim tabs.
2) As far as chasing fuel problems: All the filtration in the world won't help if the source problem still exists. You'll potentially be chasing your tail for years unless you go directly to the source: your fuel tank and upstream fuel sources. The first step I take on any old vehicle restoration is dropping or pulling the tank. It;s a no brainer for me. See: http://gastankrenu.com/ or any local shop that performs tank cleaning and re-lining. Even after you get rid of the obvious stuff, the really fine, almost invisible rust-like crap will still mess up a decent carb re-build. And remember each step in the fuel delivery chain is affected: Carb: jets, float bowl, valve seats, brass filters, Fuel pump: diaphragm, sediment bowl, Inline filters, Cutoff-valves, copper lines, etc. Also install a modern canister style, fuel filter/water separator while you're at it, they are pretty much standard equipment on today's craft and available. Change the canister once a season.
3) As far as your Prestolite Alternator: These come up on ebay once in awhile. If you find one at a reasonable price, you can practice rebuilding it yourself and you'll have spare. The are fairly simple and easy to work on. If you search the internet under ALK-6207 or OMC 383443 you will find many of the parts are still available (including the solid-state regulator) for this alternator thru BRP/OMC dealers, amazingly. One nifty feature of this Prestolite-OMC design is the external regulator is essentially water-cooled, by heat sinking the regulator to the thermostat housing. With an internally regulated alternator the solid-state electronics are exposed to higher operating temps which can get quite high. especially if the alternator is operated under heavier than normal duty cycles. Just remember to have your ALK regulator checked out along with your ALK alternator. The regulators rarely failed unless someone as incorrectly re-wired or abused the system with a 2nd battery and switched the alternator under load.
4) As far as JD's quest for an oil sender switch: This is NOT a MARINE-rated electrical part. Thus any number of vehicle application use similar or identical switches. It only needs to have matching mechanical threads. Just carry you old OMC part in and have them eyeball it and hand you something that will physically fit. Electrically it will most likely be 100% compatible. I believe this part is also still carried by OMC/BRP dealers, but it is a little more difficult to find, because only OMC Boats used the idiot light system. When OMC sold the sterndrive package to OEM boatbuilders they used "proper" water temp and oil pressure gauges, not idiot lights, thus requiring different senders. In either case, it's all based on Stewart-Warner technology dating back to the late 40's - early 50's. This shouldn't be a big deal or show-stopping task!
Lee
On Aug 8, 2009, at 10:52 PM, Scott Veazie wrote:
Hi Bill,
I had the same problem with crud on my Seasport that I used to have. The easy solution I came up with was to install a second glass inline fuel filter. I put it immediately as the line exits the tank, and this in conjunction with one near the carb did a good job of trapped all the crap. It's not ideal, but after a while you'll get there.
The second issue to mentioned I'm having as well on my 68 Seasport. Porpoising seems to be a common problem with these boats and lack of the ability to trim with the stern drive. The cheap and easy solution is to get a hydrofoil fin for the drive. I've had them before and they do wonders to kill porpoising, get you up on plane faster and at lower speeds, and cut fuel consumption. They literally do what the package says they do. I had doelfins the first time, but this time I'm going with the Sport SE 300. It costs more but is narrower and seems more rigid. I did a fair amount of research and it seemed to be the best. And for $60, it's well worth the investment.
~Scott
________________________________
Date: Sat, 8 Aug 2009 21:26:45 -0700
From: bldfw@...</mc/compose?to=bldfw@...>
To: omc-boats@...</mc/compose?to=omc-boats@...com>
Subject: [OMC-Boats] 2nd Shakedown Cruise
The first shakedown cruise of my Explorer brought to light the need for a carb rebuild and a tune up. I completed those though did have the problem with the ball bearing in the accelerator pump channel.
Today was the 2nd shakedown which went really well. She started right up on the newly rebuilt carb. I was pleasantly surprised about that. Slow increase of the throttle brought smooth increase in power. I only pushed her to about 3000 rpm but she did get up up on plane. The lake had quite a bit of chop so I know what folks have been saying about the potential of being beat to death with a rough ride. will have to take her out a couple of more times to get used to it's behavior.
Maybe it was the chop but it seemed to feel like it was porpoising or maybe I was over reacting to the new behavior.....anyone experience anything like that?
I only encountered one significant problem that's easily resolved...crap in the gas tank. There wasn't a problem until we started to hit the chop which I'm sure stirred up crud sufficient to start flowing through the fuel lines. It first started happening at 2500rpm when it would take about 20secs before the fuel bowl would drain to the point of stalling. I checked the fuel filter (glass) and could see some crud in the filter. After a moment, it could be restarted and ran fine until 2500rpms again. No big deal.
But then the longer we stayed out, the lower the rpms would get before it would stall. Eventually it got to where we could barely idle but fortunately we were on our way back to the marina. Continued fuel filter inspection showed the filter (glass type) was completely clogged with a pudding like substance. Will pull it tomorrow and check it closer.
Other than that, the engine and outdrive appeared to run just fine. The next time I take her out I'll try pushing the rpm's past 3000k to see how she performs (when I have smoother water!).
In the meantime, suggestions on best way to deal with the crud in the tank. I know the obvious is to remove the tank but having just rebuilt the interior of the boat, I'm not thrilled at the prospect of having to take it apart to get the tank out. I will if I have to but I thought I'd check with you guys to see of there's an alternative.
Bill
Dallas, TX
1970 Evinrude Explorer - 155 Buick V6 - OMC Sterndrive
http://www.photobucket.com/evinrude_explorer
-Bill
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