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Message |
    
William WhiteCloud
Member
Username: willieo
Post Number: 5
Registered: 07-2009
| | Posted on Sunday, January 10, 2010 - 08:35 pm: | 
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I am going to get a 1984 searay tommorow
There were 2 new 4.3 mercs installed. For whatever reason the previous owner installwed
2 new v-8 outdrives that he took off his fathers boat which was a 33' bayliner
Apparently the father tried to upgrade his 305s to a big block and merc outdrives. When the engines wouldbt fit in the bayliner he sold the engines and kept the outdrives which his son then put on his searay.
The problem the son had was the boat wouldn't plane so he parked the boat and 1 year later called me to haul both boats away.
Sooo my question is which outdrives are called for to push a 27' searay sundancer.
Or is there any way to change props to make up for the gearing difference?
I have a guy who wants the bayliner but not without outdrives.
Can someone lead me in the right direction? Thanks |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 506
Registered: 03-2008
| | Posted on Sunday, January 10, 2010 - 08:55 pm: |
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This one had me thinking. I like it. The new 4.3's would have the same hp as the 83 5.0's i THINK.
Might be a different reason not getting on plane.
What props you got on that barge anyway? |
Thomas McGee
Member
Username: 1973browning
Post Number: 40
Registered: 01-2009
| | Posted on Sunday, January 10, 2010 - 09:20 pm: |
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I don't think you can make up for the difference with the props. It is to much of a jump from lets say a 1:84 for the 4.3 litre to probably something between 1:47 or 1:50 (I think you would be better off to have both drives rebuilt using the proper gears for the proper engine package and I am pretty sure it is 1:84 ratio.) You could sell the drives that you have now and have a mechanic install the correct ratio upper drive units. It depends what condition the boat is in now. Is it worth it?
best of luck, Tom |
Thomas McGee
Member
Username: 1973browning
Post Number: 41
Registered: 01-2009
| | Posted on Sunday, January 10, 2010 - 09:34 pm: |
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Sorry chief I misread his post. I thought he said 350. Don't the newer fuel injected 4.3s make around 230hp? I guess an early 80s 305 would put out close to the same hp? Wouldn't you think? Would a 305 require a 1:65 ratio drive? |
William WhiteCloud
Member
Username: willieo
Post Number: 6
Registered: 07-2009
| | Posted on Sunday, January 10, 2010 - 09:52 pm: |
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Wow Thanks for the replies
I like your thinking Chief. The motors are the original he just had dthem rebuilt by an engine rebuilder.
Thomas
The bayliner started with 305s and the outdrives are for ig blocks ecause he wanted to upgrade the original motors but the big blocks wouldnt fit. Are you thinking the gear ratio is 1:84 for 4.3 mercruisers??
I am thinking of selling the outdrives and getting something to marry to these engines better. I think its worth it because I get these boats for free, So I dont think it will kill me to work on this but I am a building contractor and nobodies building so money is tight.
I dont know what the prop size is chief. Thats going to e my next search and perfect mission. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 915
Registered: 03-2009
| | Posted on Sunday, January 10, 2010 - 10:19 pm: |
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William, unfortunately, and it does not matter whether Volvo Penta or Mercruiser, there is no substitute for a correct over-all gear ratio for the engine.
The engine will/should always determine/dictate the over-all gear ratio (with a few exceptions being altitude adjustments)!
Many of the pros will tell you that trying different props will very likely never solve the problem...... as much as we'd think or like it to.
I'd suggest that you contact M/C Tech Support and ask what ratio would be correct for these engines.
You will then need to perform a WOT RPM test for proper propeller selection just as you would with any boat.
I wish you luck on this!
. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 508
Registered: 03-2008
| | Posted on Monday, January 11, 2010 - 06:32 am: |
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i must be misreading the whole thread. 300-350 for the proper upper gear set, just helped my friend rebuild his upper.
Ebasicpower had the gears. |
Kghost
Senior Member
Username: kghost
Post Number: 1177
Registered: 07-2008
| | Posted on Monday, January 11, 2010 - 06:55 am: |
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Contact Searay as they are the boat amnufacturer and will have the reccomended drive ratio information. Merc sells the power the boat manufacturer figures out the power and ratio's needed to propel it.
If it had V6 engines in it before then that is all you need for searay to give you the desired ratio. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 916
Registered: 03-2009
| | Posted on Monday, January 11, 2010 - 07:58 am: |
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quote: "If it had V6 engines in it before then that is all you need for searay to give you the desired ratio."
Kghost, when I read the first post, I saw that this info was rather vague!
However, what we do know now, is that the replacement engines are 4.3L V-6's.
I do hear William telling us what these drives are!
Quote: "2 new v-8 out drives that he took off his fathers boat....... Apparently the father tried to upgrade his 305s to a big block and merc outdrives."
It would appear to me that the drives are for SB V-8's..... If I understand him..... and that this ratio would very likely be incorrect for a 4.3L V-6.
(I think we are in agreement)
If Searay can provide this info.... that is great! I for one would still bounce this off of a M/C tech.
, |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 510
Registered: 03-2008
| | Posted on Monday, January 11, 2010 - 08:27 am: |
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no he still has the v6's i think and has 305 drives on the boat mated to the v-6's and can't get on plane.
See i misread it also cause above is whats in my mind now.
But latter for this cause i'm waiting for him to come back and post exactly whats on the boat he wants to keep and exactly post whats what cause i'm too old to understand any of this. |
Kghost
Senior Member
Username: kghost
Post Number: 1179
Registered: 07-2008
| | Posted on Monday, January 11, 2010 - 08:31 am: |
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The way I read it was,
He has two rebiult V6' engines, which are in the Searay.
He has 2 305 V8 OUTDRIVES left over from a failed big block motor exchange, they were the original ones in the bayliner,
Big blocks were tried but failed (did not fit), "big block outdrives" if this happened recently would be Bravo outdrives. They stopped alpha ones with bick blocks around '89. Thus the selling of them with the BB motors if that is the case and the 305 outdrives were left behind.
If what I read from this he has
2 rebiult V6 engines in the Searay, He has 2 305 1.50 : 1 original outdrives from the bayliner.
What he wants to know and need (again if I ubderstand this correctly) the correct ratio for the outdrive/uppergear case for the V6's which I believe is 1.84 :1.
How does that interitation sound?? |
Kghost
Senior Member
Username: kghost
Post Number: 1180
Registered: 07-2008
| | Posted on Monday, January 11, 2010 - 08:35 am: |
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1) There were 2 new 4.3 mercs installed. For whatever reason the previous owner installwed
This is the confusing part
2) 2 new v-8 outdrives that he took off his fathers boat which was a 33' bayliner
Apparently the father tried to upgrade his 305s to a big block and merc outdrives. When the engines wouldbt fit in the bayliner he sold the engines and kept the outdrives which his son then put on his searay.
They may be alpha's or bravo's. It is hard to tell but if they were purchased with the BB motors then That is what I would say.
If they are the originals from the 305's they could be either, remember it was a 33 footer............If it did not have bravo's 2 or 3 no wonder it would not plane!!! |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 917
Registered: 03-2009
| | Posted on Monday, January 11, 2010 - 09:10 am: |
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quote: "But latter for this cause i'm waiting for him to come back and post exactly whats on the boat he wants to keep and exactly post whats what....... cause i'm too old to understand any of this."
Agreed! (except for the part about being too old! LOL) |
Guy Gaspar
Senior Member
Username: guyjg
Post Number: 5537
Registered: 08-2006
| | Posted on Monday, January 11, 2010 - 12:30 pm: |
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Rebuilt 1984 4.3L engines each have 175-185 HP unless they were upgraded somewhat. Would he not need a pair of Alpha 1 Gen. 1 ODs w/1.84: 1 ratios? A WAG on the props; 14.25" to 15.25" X 19P. |
Kghost
Senior Member
Username: kghost
Post Number: 1181
Registered: 07-2008
| | Posted on Monday, January 11, 2010 - 01:33 pm: |
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Yes agreed but we are not at all sure of what he has other than the engines at this point.
Need a lot of clarification on this one........ |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 512
Registered: 03-2008
| | Posted on Monday, January 11, 2010 - 02:18 pm: |
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Hah guys get over to boater ed i have a great thread going, leave a comment, everyone would probably like to see how you got your start wrenching.
Be well ! |
William WhiteCloud
Member
Username: willieo
Post Number: 7
Registered: 07-2009
| | Posted on Monday, January 11, 2010 - 06:05 pm: |
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Wow again and thanks alot. I mean it.
The engines are 1984 rebuilt 4.3 mercruisers on a 27' SRV270 Searay. Its a project boat but the motors have 12 hours on them I checked today.
The father bought new motors and outdrives for his 33' ayliner Conquest. When he went to put the new motors in they didnt fit they were big blocks and to big. Sooo he sold the motors and left the outdrives with junior who proceded to put them on his searay with the v-6 engines. They fit bbut from what Im getting here is they're geared wong? and now the boat doesnt plane even at high rpms. He gave up and now the boat is mine
The 1981 Conquest express ( Dads) is also mine and its WIDE. It now has no motors or outdrives. Even the gimbels are gone. Just a completely empty transom bay.
They are alpha one gen1 drives so I guess that is what I'll go back with unless I can possibly regear the drives for the searay and part out the bayliner which is very nice and roomy.
Theres where Im at. I really do appreciate this site I can tell you that.
Kghost asically hit the nail on the head and Im sorry for the confusion.
Next I might repower that bayliner ut thats another thread I think
Thanks and any more advice would be appreciated
Be Well |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 516
Registered: 03-2008
| | Posted on Monday, January 11, 2010 - 06:40 pm: |
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upper gears 300-350 for the set. I recommend new bearings. another 100 bucks. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 920
Registered: 03-2009
| | Posted on Monday, January 11, 2010 - 10:25 pm: |
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If these drives are from a Mercruiser BBC engine/drive combination, these would be Bravo Drives, correct??????
So what if you were to put it like this?
The SRV270 is currently fitted with:
Boat...................... = SRV270(we all know what that is)
Engines................. = 1984 4.3L GM's
Sterndrives ............ = Bravo I, II or III (since we hear no mention of single/dual prop)}
Is the above correct?
. |
Kghost
Senior Member
Username: kghost
Post Number: 1182
Registered: 07-2008
| | Posted on Tuesday, January 12, 2010 - 06:58 am: |
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OK
You have 2 rebiult V6's with 12 hrs on them.
That combo is ~ 360 hp combined.
Th outdrives are Alpha 1 gen 1........Good!
As suggested you could call Searay and ask what was originally used for gear ratio for your boat motor combo.
Typically a V6 is matched to 1.84:1 ratio. when installed in a boat with ONE motor only.
If you get the ratio correct and find the best proppeler ( maybe a 4 blade if a counter rotation is also avalable) and I would say it should do OK.
Wont be a speed demon or anything like that but it should work. Remembher It did do fine when new........
Do some reaserch and see what you can find out about the original state of the baot when new ( power/outdrive info).
Let us know when you do.
Also a new gear set can be done, Also maybe a new upper with correct ratio.
Many options available..... |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 921
Registered: 03-2009
| | Posted on Tuesday, January 12, 2010 - 09:35 am: |
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Here is what I read, although William does mention Alpha drives:
The father bought two (2) NEW (as in current late model) BBC engines/drives for his older 1981 33' Conquest boat.
Since these were new, would it be fair to suggest that the BB engine packages would have been offered with "B" drives (BI, BII or possibly BIII's).........., not Alpha drives????? (I'm simply asking)
This is what I'd like to have clarified under the guise that William may be mistaken re; the drive ID.
(no offense, William!)
As for the boat in question.....(The SRV270 w/ sm 4.3L's) it would very likely have been originally fitted with Alpha drives.
Be that as it may, it makes little difference between B or A style drives so long as the fit can be made correctly!
What does make a difference (and at the risk of redundancy here) would be the correct over-all gear ratio for these now installed 4.3L engines in this SRV270 hull........ (and of course, an influence by the hull style and displacement!)
William, changing gears to accommodate the correct ratio may be counter productive in terms of cost for parts and set-up time.
Your call on that!
. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 957
Registered: 03-2009
| | Posted on Sunday, January 17, 2010 - 03:45 pm: |
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OK.... we need an update here! " " when ready! |
William WhiteCloud
Member
Username: willieo
Post Number: 8
Registered: 07-2009
| | Posted on Tuesday, January 19, 2010 - 11:37 pm: |
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Ok so I went out east to the Res where the boat is today and was on a mission to take down as much info as possible. And wouldnt you know it, but all of the serial #s had een painted over. I couldnt find any discernable markings to tell me where to start.
I did get an engine serial # 67258401
The part of the outdrive bolted to the transom that wasnt changed or at least I think wasnt says # c618211
Also one of the outdrives looks like an aftermarket by ("Sterndrive Engineering" SE106)
The props on the boat are 14.5- 19P
Anybody have any advice here
Thankyou |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 992
Registered: 03-2009
| | Posted on Wednesday, January 20, 2010 - 09:13 am: |
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SE would be an Alpha replacement, correct?
You may need to just simply "manually" count the input shaft revolutions relative to prop shaft revolution!
(do this "check" several times)
That would give you the " over-all" gear ratio! |
William WhiteCloud
Member
Username: willieo
Post Number: 9
Registered: 07-2009
| | Posted on Wednesday, January 20, 2010 - 09:49 am: |
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hmm Thanks ricardo but Im a little lost on that one
yes Se is an Alpha replacement apparently (check)
where should I look to count these. are you sayin put the boat in neutral and spin? hmm
I guess I could count the prop spins easy enough but the other end I might have some drama with
That does sound so simple it almost has to work though.
Where should I count up top? |
Brian Brackett
Senior Member
Username: kainon
Post Number: 1125
Registered: 03-2009
| | Posted on Wednesday, January 20, 2010 - 09:54 am: |
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Well, someone should have a receipt for this stuff ?? either current or previous owner right
has to be a serial number on the SE drives for them to keep track, call SE and ask where the SN numbers are.. and can also take the top cap off the drive use a marker anc count teeth. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 993
Registered: 03-2009
| | Posted on Wednesday, January 20, 2010 - 10:00 am: |
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William, the "Over-All" gear ratio is just that..... A ratio between the engine revolutions and the prop shaft revolutions!
Let's say we have a ratio of 1.95:1 (v/p duo prop ratio)
This means that the engine will rotate exactly 1.95 revolutions to 1 revolution of the propeller(s).
You must turn the front shaft on the drive (in the correct direction and while the drive is IN gear) and carefully determine how many rotations (and fractions of a rotation) the shaft will make for 1 full turn ONLY of the propeller shaft!
This will be your ratio.
. |
William WhiteCloud
Member
Username: willieo
Post Number: 10
Registered: 07-2009
| | Posted on Wednesday, January 20, 2010 - 10:34 pm: |
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Thank you Ricardo. Sometimes its so simple I miss it. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 540
Registered: 03-2008
| | Posted on Thursday, January 21, 2010 - 07:08 am: |
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copied and pasted here from another site:
The easiest way is to read it from the sticker. . You may be able to use the serial number to determine it too assuming someone didn't rebuild it and change it.
Barring that you can count teeth on the gears if it's apart or if removed, put it in gear, turn the drive shaft 10-20 turns or so, and have someone count the turns of the prop (you may need a protractor to measure fractions of a turn if you REALLY want to be accurate) and get out the calculator.
input shaft turns divided by propshaft turns = ratio (Yoke/Prop=ratio)
If it's a 1.5:1 or 2:1 drive it's easy.....3 turns of the yoke will produce 2 prop turns or 2 turns to 1 turn respectively.
If it's 1.43 to 1 you'll have to turn the input shaft more turns.... 143 to be precise. it would be 143 revs of the yoke to 100 revs of the prop etc.... This is where the protractor comes in handy...
For example, with a 1.43:1 drive the input shaft (engine) turns 1.43 revolutions for every 1 revolution of the prop......... If you measure exactly 1 turn of the prop. you would have to measure 1.43 "turns" of the yoke....... 0.43 times 360 degrees would be about 155 degrees.
so 1.43 turns would be 1 revolution + 155 degrees more |
