imported_Jimbo
Seaman Apprentice
- Joined
- Jul 15, 2006
- Messages
- 43
Hello!
I have a Johnson 70-97, recently re-bored and broken in. I?m running an 18 hull, fairly light about 700kg (1900lbt) including the engine. I?m doing 34mph according to the GPS at 5400 RPM at WOT. The RPM seems a bit low, but when I calculate the slip its 5%, is this actually possible or is the tach a bit on the low side? If I trim the engine further I get up to about 5600 RPM but without any increase in speed, and I can hear that the prop is running close to the surface...
What do you experts here recommend, a stainless prop to be able to trim further or a 15?instead of the 17?alu-prop I?m running now? Btw the prop is brand new (the old was in bad shape, changed it as the engine was fixed).
Am I running to low RPM:s to add a waterskier without changing the prop?
BR Jimbo
I have a Johnson 70-97, recently re-bored and broken in. I?m running an 18 hull, fairly light about 700kg (1900lbt) including the engine. I?m doing 34mph according to the GPS at 5400 RPM at WOT. The RPM seems a bit low, but when I calculate the slip its 5%, is this actually possible or is the tach a bit on the low side? If I trim the engine further I get up to about 5600 RPM but without any increase in speed, and I can hear that the prop is running close to the surface...
What do you experts here recommend, a stainless prop to be able to trim further or a 15?instead of the 17?alu-prop I?m running now? Btw the prop is brand new (the old was in bad shape, changed it as the engine was fixed).
Am I running to low RPM:s to add a waterskier without changing the prop?
BR Jimbo