Topic: Can somebody help

This topic has 7 replies, 5 voices, and was last updated 10 years, 4 months ago by JSLAW.

Viewing 8 posts - 1 through 8 (of 8 total)

Author

Posts
January 30, 2016 at 3:10 am #454973

Preacherboy
Participant

I got my new lower unit on today… Ready to go to lake tomorrow for break in. Im gonna try to stick close to break in recommendations as possible. Question is, I cant go beyond 3500 RPMs, and my tach is non functional, therefore my GPS speedo is my only indicator. (Digital to Analogue gauge conversion until this issue hit) so can anybody tell me what safe speed would keep my RPMs under 3500? I have a merc. 2.5 efi. With 25P Trophy plus.

January 30, 2016 at 3:34 am #454974

apdriver
Participant

Id say 35 MPH. I think you would be safe there.

January 30, 2016 at 3:38 am #454975

Preacherboy
Participant

Thanks Apdriver!!! That helps!!

January 30, 2016 at 3:49 am #454976

apdriver
Participant

Its just what Ive seen on the couple Ive owned until you really start packing the air under the hull where its efficient. Id say 1 mph/100 rpm up to 5000 rpms or so. Should be awfully close.

January 30, 2016 at 4:04 am #454977

Preacherboy
Participant

I appreciate it. If my motor is hurt, there wont be any need knowing, and a new engine is my future I guess, along with the Mercmonitor. But, if this lower unit is my problem solved and I can go ahead with previous plans of switching out the BP 101 to analogue gauges. So Im kinda between knowing what the future holds at this point, and holding off on a Tach etc. Tomorrow Ill know what the future holds.Thanks Again

January 30, 2016 at 8:42 am #454978

toledobasser
Participant

You have your answer and I agree. In the lower range I have seen on both my Cougar/225 and my dads Ranger/150 that the mph pretty much stays consistant with the rpms up to 4500-4700 (45-50mph). 35mph should have you very close to 3500rpms.Jim EbarbMany, LA (Toledo Bend Lake)2004 Cougar/ 225 OptimaxHumminbird Helix 12 Chirp SI on BalzOut Mount at bowLowrance HDS 7 at bowHumminbird Helix 12 Mega SI on Ram Mount at ConsoleLowrance HDS 8 in dash at console

January 30, 2016 at 9:24 pm #454979

bwp777
Participant

I didnt know there was a break in period for the lower unit. why is this?

January 31, 2016 at 3:38 am #454980

JSLAW
Participant

Yep. Mostly for the seal and bearings of the gear-case. A 1 hour run-in while under load (motor trimmed down) after that let her eat. Change the gear lube at 10-20 hours and then schedule every 100 hours or once per year with the water pump.
Author

Posts

Viewing 8 posts - 1 through 8 (of 8 total)

You must be logged in to reply to this topic. Login Register