Alpha 1 Nose Cone installation

[daren34]

the reason i ask is that you could have had a high altitude drive at 1.65 to 1

daren

that much change in ratio would exlaine the difference

most shops use the 1.5 gearset without looking to see what they were originaly

i have seen 4 cyl boats come back from the shop with 1.5 gears when they went in with 1.98gears

 

[daren34]

see if you can find a 21 mirage to borrow from someone to test and see what rpm's you get

you should see closer to 4600 to 4800

i used to run a 15x19 mirage on my starlet at 5000 rpm at about 60 mph
i did not have a gps but i could outrun most 21 foot mini offshore boats
with the 19 you could pull 2 or 3 slolam skiers at the same time m=no problemb

the prop calc shows 61 at 4400 with 1.5 to one gears and 12 percent slip

could be more or less slip but impossible to tell with out gps speed #'s

daren

 

[smallblockford]

You gained drag. think about the water that came around the bullet of the drive at 60 it isnt getting a air pocket to the prop. so you created more drag the water drags down the bullet of the drive you shouldnt have to cone it till after low 70s at that speed the water will bounce around the cone and make a draft to the prop in theory. although the cone will help out with other areas such as blow out around turns and handling around turns. more food for thought on a bravo they used to say at school it was a waste of time to cone it unless you planed on haveing the boat run past 90 because that is how long the bullet would let the pocket of water by till it created a draft by the prop.

 

[remlinger]

It may appear that the wrong gear ratio was installed. Looking in the service manual for my out drive I had noticed that a 1.32/1 ratio was offered. Using this and calculating mph based on the RPMS, pitch, slip It puts me back to where I was originally. I spoke to the service manager yesterday at the shop and he had mentioned they had installed 1.5/1 ratio. When using the rpms I'm receiving now, that gear ratio my and pitch and skil as a constant it puts my mph right at where they are at this time.

I have used a prop calculator and imputted prop pitch's of all of the props I owned and installed over the years with the rmps and mph that I was getting at that time, all of the data only works if my gear ratio was a 1.32, it did not even come close to it if I imputted the 1.5 ratio in to the program.

I will need to check the port side of the outdrive for the gear ratio stamp. however that stamp is placed on a adhereed aluminum strip which after 18 years of use fell off in Cass Lake some time ago.

So would the factory have any specs on this and if so who should I contact?

The marina already said they would replace it if they had made the mistake at no cost to me.

 

[illMATTic]

when i installed a cone on mine i lost 2 mph but no rpm loss. i was able to gain it back by by proping up and raising the engine higher with the cone.

good luck with the gear swap.

 

[Boston Predictor]

Why would they change the gears and not tell you?

 

[remlinger]

Basically they need to replace the gears due to water infiltration in to the housing due to a pour boot job by ME a year ago. He looked up in the record and seen that they installed a 1.5 to 1 gear ratio. The only thing I can think of is that they were not able to see the stamp since it is missing off the side of the out drive and installed the typical 1.5 gear.

I would not imagine that the mechanic would count the teeth, but them again they should have and are offering to look it over and replace it at their cost if they did not do the job right the first time. The head mechanic did mention that 3800 is really low for my set up and cannot see any other reason why it would have droped other than the gears being wrong.

 

[daren34]

your rpm's would be even lower with 1.32 to one gear ratio

the only way i know of to tell what gear ratio the drive came with is to get the serial number off of the drive and cross it over

the serial number is either on the back under one of the stickers or on the side under a sticker

going from a 1.32 to a 1.5 you would gain 600 rpm not lose it

the loss of rpm is most likley caused from opening up the exaust with out rejetting the carb or going with a larger carb and adding the nose cone


i dought your gear ratio was changed from 1.32 to 1.5
i was thinking you may have had a high altitude drive at 1.65 to one

daren

 

[daren34]

Is there a difference in carbs for prop exhuast boats and thru-hull exhuast boats?? I believe my stock carb is, which is a 4 barrel, is only 500 or 550 cfm. I can't imagine the carbs would be different, seems like that would affect the hp rating. Yes the boat handles and cruises great with this prop, just won't spin up like it should. Very frustrating, the motor purs like a kitten and runs great, but every one else seems to be faster and gettin alot more out of their 350's than i am.

yes the carbs would be different

you are now running it like a dragster with open headders
you need a richer carb due to the open exaust

with the through prop exaust is much like the exaust system on a car if you free up the exaust you have to add more fuel

same with any hotrod or motorcycle or boat
if you just add a bigger carb you run to rich but when you add the open exaust or cam or head changes it balences out again

some of it could be that you went to a larger diameter 23 pitch prop
usually 200 rpm for each change in pitch 500 rpm for each inch in diameter
if you like the larger prop which is probably a better prop for a sterndrive
then see if you can change it for a 21 pitch
that would bring you back up to 4400

good luck daren

 

[CheckmateFever]

yes the carbs would be different

you are now running it like a dragster with open headders
you need a richer carb due to the open exaust

with the through prop exaust is much like the exaust system on a car if you free up the exaust you have to add more fuel

same with any hotrod or motorcycle or boat
if you just add a bigger carb you run to rich but when you add the open exaust or cam or head changes it balences out again

some of it could be that you went to a larger diameter 23 pitch prop
usually 200 rpm for each change in pitch 500 rpm for each inch in diameter
if you like the larger prop which is probably a better prop for a sterndrive
then see if you can change it for a 21 pitch
that would bring you back up to 4400

good luck daren

Ok, yup i uderstand that i need more fuel dumping into the motor, but what i meant was, are the models of carbs different, like different CFM ratings. Hmm, interesting that 1 inch in dia with the same pitch would loose 500 rpms...my new prop is about 1/2 inch bigger in dia, enough where the trim tab on the drive had to be removed where it had plenty of clearance with my old 23p...i didn't think it could make that huge of a diff. Thats an eye opener...

Also, +1 on the gear ratio thing...going to higher (numerically lower) gears would loose rpms and (at least in a car) kill hole-shot. Going to a lower (numerically higher) gear ratio would do just the opposite.

 

[Big Dave]

Even on the old 305 I put in the diplomat, I had an original quadrajet on it but it had a huge vac leak. put a 625 edelbrock on it and the exh was much quieter and major loss of top end....put a 650 holley doublepumper on it and exh louder than ever with way more power.....then engine lost oil twice in same day(I was 2000 miles away at the time) so we built a 350 for it. Still use the Holley but it is not quite so rich on the 350 (76 primary, 80 secondary, plugs in place of both power valves,) has turned 5700rpm with a 14 1/2 x 22p 4 blade(Lil Dave backed out of it at that point)
I need to try a 25p but the wife gets mad every time I suggest it
We use the 22p 4blade for water skiing and wakeboarding
2 slalom skiers and 6 people in the boat and it drags a little

 

[daren34]

on the gear ratio thing
having a 1.32 gear would be like a major highway gear in a car

a 1.5 to one like a standard gear in a pickup

1.65 to one or higher like putting 4.56 gears in your truck to pull those really heavy loads with the same motor

my 4cyl 190 horse uses a 1.8 to one gear so i can use the same prop as eveyone else
otherwise if i had 1.5 to one gears i would be limited to say 19 pitch
i ran a 1.5 to one lower unit when i first got my eluder running until i could rebuild the corect drive
i was running a 19 pitch vengence 14x19 at 4700 rpm
now that i have the 1.8 gear back on it i run a 15 x 21 mirage at 5000 rpm

i run a 21 now for skiing

most v-6's run the 1.65 gear so they seem like they have more torque than
they really have

one school of thought is that you can turn a larger prop slower more effeciently
than a smaller prop faster

hopes this clears things up
i am not meaning to sound like a smartalec i just come off that way sometimes

on the carbs

holley carbs and known for performance and will outflow most other brands out of the box

quadrajets are designed to work in specific aplications
this does not mean that they are a bad carb it just takes more work to make them repond

i have run a few eledbrock carbs but never really satisfied
for my money if i was going to change carbs i would go with holley

it seems as if there were no real accurate way to tell the cfm flow of a carb
or maybe there is no set standard of testing

for example for a quadrejet to keep up on a h.o.305 in a camaro they went to 800 cfm
if you put a 800 cfm holley on the same car it would be flooding out going down the road

daren

 

[ezstriper]

from all the info I have read unless you can run solidly over 70+ a nose cone will slow you down..looks like this is another case where it holds true..sorry

 

[remlinger]

on the gear ratio thing
having a 1.32 gear would be like a major highway gear in a car

a 1.5 to one like a standard gear in a pickup

1.65 to one or higher like putting 4.56 gears in your truck to pull those really heavy loads with the same motor

my 4cyl 190 horse uses a 1.8 to one gear so i can use the same prop as eveyone else
otherwise if i had 1.5 to one gears i would be limited to say 19 pitch
i ran a 1.5 to one lower unit when i first got my eluder running until i could rebuild the corect drive
i was running a 19 pitch vengence 14x19 at 4700 rpm
now that i have the 1.8 gear back on it i run a 15 x 21 mirage at 5000 rpm

i run a 21 now for skiing

most v-6's run the 1.65 gear so they seem like they have more torque than
they really have

one school of thought is that you can turn a larger prop slower more effeciently
than a smaller prop faster

hopes this clears things up
i am not meaning to sound like a smartalec i just come off that way sometimes

on the carbs

holley carbs and known for performance and will outflow most other brands out of the box

quadrajets are designed to work in specific aplications
this does not mean that they are a bad carb it just takes more work to make them repond

i have run a few eledbrock carbs but never really satisfied
for my money if i was going to change carbs i would go with holley

it seems as if there were no real accurate way to tell the cfm flow of a carb
or maybe there is no set standard of testing

for example for a quadrejet to keep up on a h.o.305 in a camaro they went to 800 cfm
if you put a 800 cfm holley on the same car it would be flooding out going down the road

daren

Daren, i played around with multiple prop calculators imputting information and the opposite happen to the mph and rpms when at steeper prop was installed. Even on the mercruiser site it would not calculate and key you in that the mph and rmps with ptich and would not work with the gear spec'd.

Did not get out with the GPS as intended this week end, instead went to see my brother race his '69 dart 340 GTS at the Pour Stock Muscle Car Drags in Stanton Michigan.

So we'll pick up this discussion later after a little playing around.

Harold

 

[smallblockford]

the mechanic would have counted. i do and was always told throug service schools to. if it is an alpha just take the top cap off. drain the gear lube, and count the teath on the pinion and driven gear, then divide and that is your ratio easy. and it should have had a 1.50 ratio If what i have read was true, 136 would have droped the rpms big time and boat would be a real drag with out reducing the prop pitch, although the knew gear sets are not a true 1.50 to 1 like the old were they are kno 1.47 to 1 and are nernet forged.. so I do believe if they change the gears you would loose the ratio of 1.50 to a 1.47 the marina would then still run the same prop and you would see a minimal loss of rpm that the marina wouldnt of worried about.

 

[remlinger]

Results are in

Well, last day of the season at the marina on Saterday, took the boat out for one more hot lap with GPS on board.

With my wife, daughter and myself totalling in at a gross 314 pounds, 1/4 tank of gas, pair of skis, 8 life vest, 20 pound anchor, one cigar and a pack if cigerates I was ony able to turn 4200 RPMs and a disapointing 57mph.

So out comes the rubber mallet and angle grinder to remove the nose cone.

Any suggestion on prop configuration. As mentioned earlier I have 25p Mirage SS. Any similar set ups? I may wait until next year and see the outcome of removing the nose cone before switching the prop.

 

[Big Dave]

86 Diplomat w/ a hot 350 alpha 1.5gears....22p 4blade Mach Sterndriver 5700 rpm at 69.41 mph
This is our ski prop
I need to find one a little larger for top end testing, but the wife says it is fast enough now and keeps slapping my hand when I try to get to the cookie jar

 

[remlinger]

Well a new season is upon us. 11 days remaing until the boat hits the water. Only time will tell whether the noise cone helps or hurts.

I was going to uncover and work on the boat this weekend but as it goes in Michigan we're getting up to 5 inches of fresh snow today through Saterday.

So until it warms up enough to work outside the rubber mallet and angle grinder remains a good distance from the out drive. But when it happens you can be sure that I'll post the results of my experiment.

 

[Big Dave]

Hope that white stuff is gone on tuesday, I have to come up there and pick up a load of cars

 

[remlinger]

Depends on where you are going. I still have 4" on the ground, buts it's been here since last year before Thanksgiving and Southern Michigan south of I-94 received some where around 8" this past Friday. But it was 38 degrees yesterday and most of the new snow melted.

I'm about 1hr north of Detroit and in a snow belt that starts on the west coast and stretches across the state to the east so it's hard for me to judge what anyone got 20mins. south of me.