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| Yam 90 on tunnel 18ft only gets 3800 ... |
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Norman B Grantham
New member
Username: realbricky
Post Number: 1
Registered: 10-2009
| | Posted on Sunday, October 25, 2009 - 07:56 pm: | 
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I've got an 18ft G3 Tunnel with a 90 2 stroke Yamaha. Dealership installed 4 blade SS prop with a (17 pitch I think). I only got 30 mph at 3800 rpm max. I borrowed a friends prop off his 60 hp yamaha and now I get 34 mph at 5200 rpm. Is this where I should be or can I get more speed. My friend says he can go 34 with his 60 on an 18ft ( not a tunnel). |
jamie campbell
Advanced Member
Username: outboard_doctor
Post Number: 692
Registered: 02-2009
| | Posted on Monday, October 26, 2009 - 03:22 am: |
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Your boat should go alot quicker it sounds like the outboard is mounted too low check where the cav plate is at full speed and post back |
Norman B Grantham
New member
Username: realbricky
Post Number: 2
Registered: 10-2009
| | Posted on Wednesday, October 28, 2009 - 06:44 am: |
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Thank you I will try raising a little. G3 also got back with me and recommended a prop that appears much smaller and with less pitch. I will definitely use your suggestion, been wanting a hijacker anyway. |
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