Alpha 1 gear ratio problems

[aqua rat]

G,day i was wondering any one out there can help as have encounted a problem that even mercruiser marine can not give me a straight answer. I have a 7m signature with a 210hp V6 inboard mercruiser with a Alpha 1 leg 2 series i have just bought.Problem is its suppose to rev out to 4400 4600rpm and i can only get 4000rpm i have spent lots of money on efi jet cleaning and trouble shooting to having the mehanic tell me he spoke to mercruiser and they said i have the wrong gear ratio i should have a 2 to 1 gear ratio not the 1-1.62 i have on the back and changing the prop i have (4 blade 17p solas) will not fix the problem which he tells me $ 3000 it will cost me to replace the gears. i have rang mercruiser in bris and sydney and the give different answers.
If anyone can explain or have similar set ups and know what the gear ratio is it would be greatly appreated
Cheers kev.

[BM]

Kev,

Do you have a stock 3 blade prop for testing purposes? The 4 blader will be sapping top end rpm to begin with.

Your hull - tell us more. Is it antifouled? Antifoul robs hundreds of rpms if it is rough. A friend of mine cleaned the antifoul off his Southwind UB recently and with a clean bum he picked up 500rpm.

Cheers

[aqua rat]

Bm no its always been on a trailer so there is no antifoul on the hull everyone i have talked to has told me to go the 4 blade prop with this combo.I am going to go down to a 15p prop i was just hoping other people could tell me all confirm this gear ratio is normal all that iam in fact wasting my time changing the prop.

[BM]

If you originally had a 3 blade 17p prop then switching to a 4 blade 17p prop will definitely be the wrong prop.

I would experiment with a 17p 3 blader first. If that is ok then a 4 blade 15 might be ok.

I'll get back to you on the gear ratio.

Cheers

[aqua rat]

BM it orginally had a 17p 4 blade at 4000max rpm i need between 4400 to 4800rpm i hope that a 15p 4 blade will fix the proplem but the marine merhanic tells me it wont 1-1.62 is the wrong gear ratio for this outfit.

[The codfather]

Try Ebay as there are some American dealers on there that have what you are after a lot cheaper than you'll get in Aussie,

also SEI have replacement drives cheaper than you have been quoted for the gear set with 12 mths warranty may now be 3 years

I never buy spares in australia anymore as i got sick of being ripped off

http://www.sterndrive.cc/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=116AUC

cheers
Ray

[BM]

BM it orginally had a 17p 4 blade at 4000max rpm i need between 4400 to 4800rpm i hope that a 15p 4 blade will fix the proplem but the marine merhanic tells me it wont 1-1.62 is the wrong gear ratio for this outfit.

I would be trying a 15P 3 blade. That should lift your rpm by at least 500rpm. If a 15P 3 blader fixes your rpm then I would say the ratio is correct for the application.