Texas Fishing Forum

Jasper lower unit?

Posted By: stratos1

Jasper lower unit? - 12/25/15 11:19 PM

Can a lower unit cause loss of rpm ? And why ?
Posted By: Dubee

Re: Jasper lower unit? - 12/26/15 02:17 AM

Yes
Posted By: kingdad101

Re: Jasper lower unit? - 12/26/15 03:29 AM

does it have the same gear ratio as the old one...
Posted By: stratos1

Re: Jasper lower unit? - 12/26/15 02:52 PM

It has the gear ratio as the motor year calls for,1998 Evinrude 225. Dubee, you say yes. Besides gear ratio how?
Never checked the ratio before the other one trashed, so really don't no.
Posted By: TLW

Re: Jasper lower unit? - 12/26/15 03:47 PM

how many rpm lost?
Posted By: stratos1

Re: Jasper lower unit? - 12/26/15 04:05 PM

between 400 to 500 rpms
Posted By: Flippin-Out

Re: Jasper lower unit? - 12/26/15 04:13 PM

Could the prop have been damaged (bent) and not noticed?
Posted By: stratos1

Re: Jasper lower unit? - 12/26/15 04:14 PM

Had the pitch on the prop changed from 24 to 22, got rpms back up to 5800. What is weird is the 24 pitch 4 blade will run 6000 rpms. Both are 14 1/4.
The rpm drop was right after new lower unit put on.
Posted By: stratos1

Re: Jasper lower unit? - 12/26/15 04:15 PM

No prop damage.
Posted By: Dubee

Re: Jasper lower unit? - 12/26/15 04:37 PM

Could be gears not meshing correctly.
Posted By: TLW

Re: Jasper lower unit? - 12/26/15 04:41 PM

sounds like a different gear... if something wrong and/or bad in tha gear case usually it (or motor) isn't long for this world...
Posted By: stratos1

Re: Jasper lower unit? - 12/26/15 06:16 PM

Does to me to.
Posted By: LOSTTEXAN

Re: Jasper lower unit? - 12/27/15 05:04 AM

I'm thinking Different gear.

You haven't talked about GPS speed difference, which would clue us in.
Posted By: stratos1

Re: Jasper lower unit? - 12/27/15 03:22 PM

Went from right at 70 to 62 gps.
Posted By: gary purdy

Re: Jasper lower unit? - 12/28/15 12:01 AM

Sounds like you got a 1.75-1 instead of a 1.86-1
Posted By: stratos1

Re: Jasper lower unit? - 12/28/15 04:06 PM

Guess need to check again.
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