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Old 12-20-2015, 06:08 PM   #1
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Default 2300 SR questions

Hello all, new member here. Anyways, just a couple questions if anyone can answer. 1) Have 7.4l w/bravo iii, what was the factory prop size? And 2.) when trimmed out on plane, the trim is slightly above full down position. The "sweet spot" is very narrow before it starts (cavitating?) Thanx for any replies.
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Old 12-20-2015, 06:19 PM   #2
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Welcome aboard.

What year is the boat.

Mercruiser has a prop calculator that will give you a recommend prop size.

Weight distribution can impact trim, how many people do you have on board and gear location. Try moving some of that around.
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Old 12-20-2015, 06:35 PM   #3
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Thanx for quick reply! Its a 2000, will take a look at the calculator. It currently has 26p's on it, was thinking about replacing them with 24's. The couple times i've taken it out, it was with wife and 2 small children and half tank of gas. This is my first experience with boat with i/o. Was thinking that the trim would be somewhere around the neutral zone instead of close to full down.
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Old 12-20-2015, 09:49 PM   #4
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What is the WOT? Should be around 4800 rpm.

What do you mean by neutral trim? Typically most of the way down is normal. Prop shaft should be parallel to water surface.
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Old 12-20-2015, 10:29 PM   #5
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Don't have accurate WOT, the rpm gauge reads something different each time. Was going to check the wiring connections next time i'm home. The "neutral trim" I was referring to is what is indicated on the trim gauge. Like I said, this stuff is new to me, so if trim is close to full down and is the "norm" then I guessing i'm trimming it correctly.�� However, by looking at these illustrations, my boat should be plowing or bow down. These are probably very generic references. Thanx again for your input.

http://www.boatus.com/Assets/www.boa...lustration.png
http://www.boatus.com/Assets/www.boa...sterndrive.png
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Old 12-21-2015, 01:54 AM   #6
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Dont know WOT, the tachometer fluctuates quite a bit, need to check out wiring/connections next time home. As far as "neutral trim" im just refering to what the trim gauge indicates (full up/full down). So while i'm cruising the trim gauge shows that the bow would technically be nose down considerably. But, if your saying that its usually normal to have the trim slightly "UP" from the full "Down", than i'm doing it right. Hopefully, didnt confuse you��
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Old 12-21-2015, 03:22 AM   #7
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The trim gauge is a rough indicator as it shows from full trim IN (down) to trim out (up) which is trailer position.

The bottom quarter of the gauge is all you'll see the needle move when running.

It may be out of alignment as well. The sendor is located on the side of the gimbal ring and has two screws to loosen so it can be rotated to adjust.
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Old 12-21-2015, 06:01 AM   #8
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Not clear on what you're referring too as 'neutral trim'. The outdrive will give you about 6 'click's' out before the trim limit sensor kicks in. My trim gauge hasn't worked in years, however if I recall trim out went from In to about the middle of the gauge. From the middle of the gauge to all the way Out was handled by the Trailer button.

The sweet spot is trimming drive out until you hear it cavitate, then click In until it stops.

To me it sounds like you're trimming the drive all the way to the trim limit.
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Old 12-21-2015, 02:47 PM   #9
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Do you have trim tabs on your boat?
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Old 12-21-2015, 05:45 PM   #10
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Quote:
Originally Posted by mmwjr View Post
The trim gauge is a rough indicator as it shows from full trim IN (down) to trim out (up) which is trailer position.

The bottom quarter of the gauge is all you'll see the needle move when running.

It may be out of alignment as well. The sendor is located on the side of the gimbal ring and has two screws to loosen so it can be rotated to adjust.
Ok, thats where the trim is when in cruise. Thats all I needed to know, that it is normal to be in the bottom half of the trim gauge. 👍 Thanx again for the replies.

Dont have trim tabs yet, but was entertaining the idea.

This boat has 26P props, are these factory or changed out?
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Old 12-22-2015, 12:40 AM   #11
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I would think you are over proped with 26P, what does the calculator suggest?

IMO you will deffinetly benefit from trim tabs in keeps the bow down when getting onto plane. That big blocks weight makes her stern heavy.
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Old 12-22-2015, 01:13 AM   #12
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I would think you are over proped with 26P, what does the calculator suggest?

IMO you will deffinetly benefit from trim tabs in keeps the bow down when getting onto plane. That big blocks weight makes her stern heavy.
Thats what i'm thinking. Like I said, the tachometer is unreliable (bounces around) need to fix. The calculator is showing 24P using general numbers.
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Old 12-22-2015, 01:37 AM   #13
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The tach sense comes from the negative terminal of the ignition coil, grey wire.

Try cleaning connections but it's no unheard of for the tach to be bad.
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Old 12-22-2015, 02:02 AM   #14
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Quote:
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The tach sense comes from the negative terminal of the ignition coil, grey wire.

Try cleaning connections but it's no unheard of for the tach to be bad.
Thank you for info. Got this boat just a few months ago. It had been sitting for a few years, so its got a few gremlins that need work on, but nothing too bad.👍
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Old 12-22-2015, 02:05 AM   #15
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Understood, not that uncommon.

Feel free to post questions.
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Old 12-22-2015, 03:27 PM   #16
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A 7.4 in a 2300 is a big engine. I didn't even know they shipped with that option. Normally I would say a 24P would be too high, but on that boat engine combo, I would try it out first. I agree 236P sounds too high as well.

Before you do anything, get it on the water and get the RPM's at WOT. If you're within the RPM range of the engine (4400- 4800 RPM) then your fine. If you're below 4400 rpm's, then drop to a 24 Pitch. If you're REALLY below 4400, consider dropping to a 22. I suspect you'll be able to pull off a 24P. Only running it will tell.
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Old 12-22-2015, 04:42 PM   #17
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Quote:
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A 7.4 in a 2300 is a big engine. I didn't even know they shipped with that option. Normally I would say a 24P would be too high, but on that boat engine combo, I would try it out first. I agree 236P sounds too high as well.

Before you do anything, get it on the water and get the RPM's at WOT. If you're within the RPM range of the engine (4400- 4800 RPM) then your fine. If you're below 4400 rpm's, then drop to a 24 Pitch. If you're REALLY below 4400, consider dropping to a 22. I suspect you'll be able to pull off a 24P. Only running it will tell.
Exactly what I was going to do next, just need to troubleshoot tachometer. Thanx for reply!
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Old 12-26-2015, 04:52 PM   #18
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Hey, have a issue that just came up with the trim. The trim "up" does not work, but the trailer "up" does. Its weird, just 2 weeks ago it worked, and now it doesnt. Thanx for any advise.
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Old 12-26-2015, 04:58 PM   #19
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Quote:
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Hey, have a issue that just came up with the trim. The trim "up" does not work, but the trailer "up" does. Its weird, just 2 weeks ago it worked, and now it doesnt. Thanx for any advise.

Bad trim limit switch. It's on the side of the gimbal ring (puck shaped) look for broken wires. Most likely needs to be replaced but I would wait until it's time to replace the bellows because of what's involved to get access to where the wires penetrate the transom assembly.
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Old 12-26-2015, 05:54 PM   #20
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Thanx for reply. I just had boats fuel injectors serviced last week, do you think they could have knocked wire loose or off while servicing?
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