1979 260 weekender what ratio and prop should i run

[DuelingProps]

well we just got a 15.25 x 15pitch alum prop yesterday and that seemed to make a world of difference down low in the revs, although she would only spin about 2800 at like 13mph at full throttle which seemed really weak so we tried manually giving it throttle at the carb and got the boat to about 3500 rpm at 25mph... finally on plain and moving nicely. So I'm guessing we need to tighten up the throttle cables and do some more tuning. the carb is the old oem "Quadra junk carb" as tail chaser so i may replace it with a new Edelbrock marine carb like chaser said. does any one have a writeup on tuning or replacing these carbs?

 

[Tail Chaser 661]

well we just got a 15.25 x 15pitch alum prop yesterday and that seemed to make a world of difference down low in the revs, although she would only spin about 2800 at like 13mph at full throttle which seemed really weak so we tried manually giving it throttle at the carb and got the boat to about 3500 rpm at 25mph... finally on plain and moving nicely. So I'm guessing we need to tighten up the throttle cables and do some more tuning. the carb is the old oem "Quadra junk carb" as tail chaser so i may replace it with a new Edelbrock marine carb like chaser said. does any one have a writeup on tuning or replacing these carbs?

The 600 CFM come preset very close.
The instructions will give you fine tuning info.
You will also need a spacer for Small block Chevy.
The steel fuel line from pump to carb will not fit.
Need hose barb fittings with 3/8" marine grade fuel hose from pump to carb.
I bought all my stuff at a speed shop. Except the fuel hose.

Maybe your throttle cable end barrel screw came loose.
The inner cable will slip if that happens. Not letting you open the throttle up. If that happened a new carb will do the same thing. Make sure all the outer cable hardware is mounted also. Same result as the inner cable loose.
Get yourself a SELOC service manual. I covers just about anything you will ever need.

 

[brains06]

The 600 CFM come preset very close.
The instructions will give you fine tuning info.
You will also need a spacer for Small block Chevy.
The steel fuel line from pump to carb will not fit.
Need hose barb fittings with 3/8" marine grade fuel hose from pump to carb.
I bought all my stuff at a speed shop. Except the fuel hose.

Maybe your throttle cable end barrel screw came loose.
The inner cable will slip if that happens. Not letting you open the throttle up. If that happened a new carb will do the same thing. Make sure all the outer cable hardware is mounted also. Same result as the inner cable loose.
Get yourself a SELOC service manual. I covers just about anything you will ever need.

I agree, check the integrity of your carb before you go replacing it. If you were able to play with it and get it to 3500...and 25 mph then it sounds as if it flows fine when it gets the message to do so, just get the "messenger" all fixed up and you should be runnin well. Drop in a new carb and I think you'll just have a 500$ paper weight.

 

[BillyT0020]

Glad some of you guys are getting your issues figured out. Unfortunately this weekend I am even more stumped and now think the boat is going to have to be pulled. I am hoping that I just trashed the outdrive when I ran it for 10 mins without a thrust washer the first time out. That's probably the best case scenario with the worst case scenario being that I trashed my brand new engine coupler that was put in last year :smt021 .

Anyway this weekend I swapped the prop again to a stock 15.25 x 15 aluminum. I didn't go WOT because at 3500 RPM's I was getting a whole whopping 11 mph on GPS. I also had a very weird noise on Sunday when I started my boat. I had to give it a little gas to fire and heard a grinding noise at about 1500 RPMs in Neutral. Wasn't the engine, I am thinking it was in the area of the coupler or upper outdrive and only happened when you throttled up in nuetral an then after the boat warmed up it was no longer there. THEN when I was pulling out of the dock, I put the boat in nuetral from reverse and it stayed in reverse! Did the same thing when I was docking. If I am in forward then it goes into nuetral fine but from reverse to neutral it stays in reverse:huh:. So anyway I am hoping its the drive with the new problems and not the coupler. I would really HATE to have the engine pulled AGAIN!!

 

[Tail Chaser 661]

I agree, check the integrity of your carb before you go replacing it. If you were able to play with it and get it to 3500...and 25 mph then it sounds as if it flows fine when it gets the message to do so, just get the "messenger" all fixed up and you should be runnin well. Drop in a new carb and I think you'll just have a 500$ paper weight.

I paid 300.00 for the carb and the same for the MSD ignition.
That was five seasons ago. Bought them at a discount speed shop.
There is a saying......
If it Ain't broke, Dont fix it

 

[Tail Chaser 661]

Glad some of you guys are getting your issues figured out. Unfortunately this weekend I am even more stumped and now think the boat is going to have to be pulled. I am hoping that I just trashed the outdrive when I ran it for 10 mins without a thrust washer the first time out. That's probably the best case scenario with the worst case scenario being that I trashed my brand new engine coupler that was put in last year :smt021 .

Anyway this weekend I swapped the prop again to a stock 15.25 x 15 aluminum. I didn't go WOT because at 3500 RPM's I was getting a whole whopping 11 mph on GPS. I also had a very weird noise on Sunday when I started my boat. I had to give it a little gas to fire and heard a grinding noise at about 1500 RPMs in Neutral. Wasn't the engine, I am thinking it was in the area of the coupler or upper outdrive and only happened when you throttled up in nuetral an then after the boat warmed up it was no longer there. THEN when I was pulling out of the dock, I put the boat in nuetral from reverse and it stayed in reverse! Did the same thing when I was docking. If I am in forward then it goes into nuetral fine but from reverse to neutral it stays in reverse:huh:. So anyway I am hoping its the drive with the new problems and not the coupler. I would really HATE to have the engine pulled AGAIN!!

WOW!.... Major bum deal.
At this point, If your comfortable, and have a place to work on your boat. I think I would try to save a whole lot of labor.

I picked up a 1 ton chain hoist at harbor freight for 35.00.
Looks like 70.00 in lumber using 4" x6" and 4x4's building an A frame for the hoist.
With all the money saved on labor. Maybe upgrade to a Basic Alpha 1. They are rated for 300 HP.
Perfprotech has good prices on transom assemblies.
And brand new drives go for 1200.00 Rebuilds even cheaper.

Possibly what ever let go has been your problem all along.
I would hate pouring money into a very weak drive. If that's what broke.
Good thing the old 26' Sea Rays are such good boats.
Really sucks that happened. Its the real piss off of boat ownership.

Dang Billy,
I just noticed your boat is not on a trl.
That really hurts. :smt089

 

[BillyT0020]

WOW!.... Major bum deal.
At this point, If your comfortable, and have a place to work on your boat. I think I would try to save a whole lot of labor.

I picked up a 1 ton chain hoist at harbor freight for 35.00.
Looks like 70.00 in lumber using 4" x6" and 4x4's building an A frame for the hoist.
With all the money saved on labor. Maybe upgrade to a Basic Alpha 1. They are rated for 300 HP.
Perfprotech has good prices on transom assemblies.
And brand new drives go for 1200.00 Rebuilds even cheaper.

Possibly what ever let go has been your problem all along.
I would hate pouring money into a very weak drive. If that's what broke.
Good thing the old 26' Sea Rays are such good boats.
Really sucks that happened. Its the real piss off of boat ownership.

Dang Billy,
I just noticed your boat is not on a trl.
That really hurts. :smt089

I spoke to a mechanic yesterday and he dosn't think running the prop without the thrust washer would have any effect on the engine coupler, especially since its brand new last year. He said the only time you wear down the gears of a coupler is when the engine is out of alignment. Im sure my marina set the engine alignment when they replaced my gas tank this winter so Ill quit worrying about that until they swap drives and have a look at it.

I did find a rebuilt Alpha One Gen One drive for sale near Detroit by a certified Merc Mechanic who went throught he entire thing. Im going to scoot up there tomorrow and pick it up and drop it off at the Marina. I do have a trailer for my boat but its kind of useless because I don't have a truck big enough to pull my boat out of the water. Anyway Ill have the Marina pull the boat this weekend swap drives, check out the coupler (just to be safe) and the shift cables while the drive is off and have it re-splashed. Shouldn't be more then an hour labor if all they are doing is swapping drives. All in all Ill be looking at about 1000 with the drive, hoist fee's, and an hour of labor. Could be a lot worse I suppose.

I think the problem with my current drive is a combination of blow by and maybe some trashed gears somewhere in there. When I ran the prop without the thrust washer it ground the case of the lower that the prop sits inside of down about a quarter inch. So when the washer was put back in the gap between the thrust washer and case is larger then it should be, which allows exhaust gasses to escape around the prop instead of through the center, causing it to slow down. So while I was getting the proper RPM's out of my engine I don't think the prop was spinning as fast as it should have been causing the low speeds. Atleast thats what I am thinking. I might be able to get away with just replacing the lower but I got a good deal on the drive and peace of mind having an Alpha One minus the pre-alpha as welll as ruling out the outdrive should anything else happen is a good thing.

Ill let you guys know how it goes when I get the new drive on and am able to test her out.

 

[helms1200]

Hey Billy, Will a Alpha 1 bolt right up or is there some modification required? My outdrive just started making some noises with a little vibration when i turn the wheel sharp left and right that i am starting to worry about. Just wondered if this might be an option for me if turns out to be a pricey fix.

 

[BillyT0020]

Yup an Alpha One Gen One will bolt right up. The only difference I am aware of between the pre alpha and alpha one is a preload pin in the top of the vertical shaft. They eliminated this in the Alpha One Gen One.

 

[26sxl]

helms1200, sounds like u-joints or gimble brg. to me..

 

[BillyT0020]

Update.
Finally got the boat pulled and the Alpha 1 installed. Ran it all weekend and am amazed at the difference in how the boat runs. At 3500 RPM's with a 14.5 x 17" SS Vengeance Prop the boat cleanly stays on a Plane and runs around 30 mph. I did take it up to 4000 RPM's and there was still plenty left in the throttle but I did not go WOT (just because I was going plenty fast enough!) Erie was pretty smooth all weekend and it was just me and the admiral onboard with 50 gallons of fuel.

After all the talk of the underpowered SB 350 I was really pleased with how the boat performed and can take a very long time rebuilding the 454 I have.

I am chasing down a small running hot condition after shutdown and unfortunatley think I was the recipeint of a "bad" new impeller but I'll get that worked out in a couple of weeks.

Thanks to all!

 

[brains06]

hey thats great to hear! You said the alpha just bolts on with only that pin modification? Hmmm...I may have access to an alpha and if I can get that kind of performance out of it (30 @3500..or close to it) then I just might take a closer look at it.

 

[BillyT0020]

hey thats great to hear! You said the alpha just bolts on with only that pin modification? Hmmm...I may have access to an alpha and if I can get that kind of performance out of it (30 @3500..or close to it) then I just might take a closer look at it.

Yup, its a straight bolt up. There's no modification on your part, the internals are just a little different. Regardless I'm happy, except for the waterpump swap that's in my near future which requires hauling the boat. Again..... :smt013

 

[brains06]

Yup, its a straight bolt up. There's no modification on your part, the internals are just a little different. Regardless I'm happy, except for the waterpump swap that's in my near future which requires hauling the boat. Again..... :smt013

Yeah, that sucks but its a short job and if you plan it right you wont miss any time on the water....(that never happens tho).

Keep us posted on your observations with the new outdrive. I'd be interested to know how it affects the overall performace of your boat. Acceleration, cruise and top speed and fuel burn in relation to the pre-alpha.

 

[Tail Chaser 661]

Update.
Finally got the boat pulled and the Alpha 1 installed. Ran it all weekend and am amazed at the difference in how the boat runs. At 3500 RPM's with a 14.5 x 17" SS Vengeance Prop the boat cleanly stays on a Plane and runs around 30 mph. I did take it up to 4000 RPM's and there was still plenty left in the throttle but I did not go WOT (just because I was going plenty fast enough!) Erie was pretty smooth all weekend and it was just me and the admiral onboard with 50 gallons of fuel.

After all the talk of the underpowered SB 350 I was really pleased with how the boat performed and can take a very long time rebuilding the 454 I have.

I am chasing down a small running hot condition after shutdown and unfortunatley think I was the recipeint of a "bad" new impeller but I'll get that worked out in a couple of weeks.

Thanks to all!

Thats some really good numbers Billy.:thumbsup:
Might be worth toying with the idea of going with a crank driven impeller.

 

[BillyT0020]

Thats some really good numbers Billy.:thumbsup:
Might be worth toying with the idea of going with a crank driven impeller.

I was actually thinking the same thing. That would entail drilling a new thru-hull and putting an impeller on the bottom of the bilge. I may wait an do it in the offseason but it would def be a great thing to not have to pull the boat to replace the impeller!

 

[brains06]

I was actually thinking the same thing. That would entail drilling a new thru-hull and putting an impeller on the bottom of the bilge. I may wait an do it in the offseason but it would def be a great thing to not have to pull the boat to replace the impeller!

So what are your observations so far with the new outdrive? Have you tried any other props?

 

[BillyT0020]

So what are your observations so far with the new outdrive? Have you tried any other props?

No not yet. Been pretty happy with the 14.5 x 17P SS Vengeance. It is getting a little vibration though so I may throw on the 14.5 x 15 P cupped SS Vengeance I have and see how she runs with that prop while I have the 17P refurbished. I have noticed that with just me and the girl the boat runs perfect with the 17, but with 4 or more people I have to run her at higher RPMs to stay on a plane. I am thinking if I put the 15P on then she will be quicker to pop up with a heavier load but I will loose some speed in the process. I'll let you guys know when I try it.

 

[brains06]

No not yet. Been pretty happy with the 14.5 x 17P SS Vengeance. It is getting a little vibration though so I may throw on the 14.5 x 15 P cupped SS Vengeance I have and see how she runs with that prop while I have the 17P refurbished. I have noticed that with just me and the girl the boat runs perfect with the 17, but with 4 or more people I have to run her at higher RPMs to stay on a plane. I am thinking if I put the 15P on then she will be quicker to pop up with a heavier load but I will loose some speed in the process. I'll let you guys know when I try it.

that engine is workin real hard to spin that 17p...trust me, the 15p is the way to go. 16 max. I'm stuck between the two. I liked the 16 better for just me but the 15p is good for a load of people and stuff too cuz the engine is already workiin harder with the weight...lets not add extra mass to the wheel too!

 

[brains06]

fuel economy is improved too. You'll find that even though you lose some speed, you'll run at lower RPMs to get to the desired speed so it balances out.