Help please...

[trigger22]

I am running a mercury 115 efi 4 stroke on an SV1900 Sea Pro. Whenever I initially bought the boat in 2007 I was getting 44 off of GPS at 5900 rpms and am now only getting 34-35 at 6400 rpms and hitting rev limiter. I bought a new prop in exact same size and pitch and it's doing the same thing. I also changed out the hub assembly and still nothing has changed. I am currently running a 14 pitch Mercury Vengeance Prop with 13.375 diameter. My question is, could there be anything else causing my rpm issue, or do I need to step up to a larger prop? I would like to be back down at 5900-6000 rpms so I would assume that I would need to bump up to a 16p prop if the prop is the route I needed to go. Thanks for any help on this issue.

 

[trigger22]

Re: 2007 Mercury 115 4 Stroke

Re: 2007 Mercury 115 4 Stroke

btt....

 

[Benny and his jets]

Re: Help please...

When your RPM's went up and your speed down, were you using the same prop when you went 44 at 5900 rpms? If so, it sounds like an engine issue or something or perhaps you're not using the proper trim?

I am running a mercury 115 efi 4 stroke on an SV1900 Sea Pro. Whenever I initially bought the boat in 2007 I was getting 44 off of GPS at 5900 rpms and am now only getting 34-35 at 6400 rpms and hitting rev limiter. I bought a new prop in exact same size and pitch and it's doing the same thing. I also changed out the hub assembly and still nothing has changed. I am currently running a 14 pitch Mercury Vengeance Prop with 13.375 diameter. My question is, could there be anything else causing my rpm issue, or do I need to step up to a larger prop? I would like to be back down at 5900-6000 rpms so I would assume that I would need to bump up to a 16p prop if the prop is the route I needed to go. Thanks for any help on this issue.

 

[Mike Zee]

Re: Help please...

14p prop. I think you may have put on an incorrectly pitched prop. Why did you buy the new prop? You should not have dropped speed and gained rpm, maybe a lower end issue? Hit anything., reason for new prop?

 

[trigger22]

Re: Help please...

Whenever my RPM's were initially running at 5900 and jumped to 6400 I was using the original prop. My prop had been worn down from sand bars and oyster bars. Once the rpm's began to rise I removed the prop and had it repaired by a local prop shop. The repairs did not make any changes. I then decided to buy the new prop exact same make and size as well as a new hub assembly. I installed the new prop and hub and ran the boat again and was still running up to 6400 RPM's and that is with half trim. I am wondering if there is some sort of slippage on the inside, and if so how would I be able to find out? I assumed that if the clutch dog was slipping there would be metal shavings in my lower unit oil but when I drained it there wasn't any. I know the RPM increase is not an indication error with my tach as well because I have the decrease in speed from the gps and also get the alarm beep for overspeed if I trim up past half way.

 

[trigger22]

Re: Help please...

The 14p prop is what the Mercury prop selector calls for and was the prop that was installed by the dealer when I bought the boat. It ran great for roughly 200 hours at 44 mph and 58-5900 rpms.

 

[trigger22]

Re: Help please...

The hub assembly that I installed is the flo torque II, which is the hub that was suggested to me by the dealer; however, my manual suggests the flo torque III. The only difference in the two hub assemblies from what I gather is the flo torque III was designed to reduce prop rattle. Is this correct, or is it possible a flo torque III could resolve my issue?