| Author |
Message |
    
David Luu
New member
Username: unix1111
Post Number: 3
Registered: 10-2009
| | Posted on Monday, November 09, 2009 - 09:05 am: | 
|
Hello,
drive: alpha1 gen 2
Afer letting engine warm up to 160 deg.(145 thermostat installed), run the boat up to 3800rpm, my temp. gauge goes in reverse, goes down to 100 deg., backing off to 1200 rpm, temp. gauge goes back to normal 160 deg. No over heat aLarm? Checked riser temps. with infrared temp. gun, risers between 170-185 deg.
David |
Brian Brackett
Senior Member
Username: kainon
Post Number: 1034
Registered: 03-2009
| | Posted on Monday, November 09, 2009 - 09:24 am: |
|
well, to check proper gauge operation touch the sender wire to ground, if it pegs at max temp, it's OK.. now about the temp dropping, you could have an issue where at idle the impeller isn't providing enough cooling, then when you increase the RPMS.. it works as it should and overcomes the heat generation of the engine. Or there's a restriction but the impeller overcomes it. |
David Luu
Member
Username: unix1111
Post Number: 4
Registered: 10-2009
| | Posted on Monday, November 09, 2009 - 09:46 am: |
|
Hello,
Thanks Brian,
I feel the temp. gauge is working as should, temp. gauge moves as temp. of engine rises when engine first starts and is idling to warm up temp.
The impeller is able to hold temps. steady at idle and at higher rpm. When running on plane, temp. gauge goes in reverse shows engine temps. getting too cool, below normal operating temp. of 160 deg. Port risers also feel hot.
When I back off the rpms, temp. of engine goes to normal.
David |
Guy Gaspar
Senior Member
Username: guyjg
Post Number: 5473
Registered: 08-2006
| | Posted on Monday, November 09, 2009 - 12:05 pm: |
|
Replace the impeller as Brian mentioned. Thermostat should be 160 F.? Replace it also. |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 341
Registered: 03-2008
| | Posted on Tuesday, November 10, 2009 - 08:46 am: |
|
You boat in saltwater? Ever change the risers if yes?
7-8 years long time for risers in saltwater,even if you flush after every use. |
David Luu
Member
Username: unix1111
Post Number: 5
Registered: 10-2009
| | Posted on Tuesday, November 10, 2009 - 09:04 am: |
|
Hello,
Yes, I'm in saltwater, changed the risers and manifolds two seasons ago.
Changed impeller start of this season.
David |
chiefalen
Advanced Member
Username: chiefalen
Post Number: 345
Registered: 03-2008
| | Posted on Tuesday, November 10, 2009 - 10:24 am: |
|
and the flapper / shutters were in place? I see you know your chit, and taking care of the " Baby ".
Maybe just maybe you went thru some sand f--ked up the impeller, or housing.
Or a bad impeller from new heard a bunch of bad ones came out and were just bad and went in alot of boats not your fault ether way.
I'm hoping just the impeller is bad.
Good luck ! |
Chris Dauth
Member
Username: chris17744
Post Number: 90
Registered: 12-2008
| | Posted on Tuesday, November 10, 2009 - 04:40 pm: |
|
Thermostat is stuck open. Low revs, low water flow, temperature normal. Hi revs, large water flow, cools motor down, Gauge reads backwards.
He only checked the Riser/ manifolds with the IR gun and they always have full water flow and not controlled by the thermostat. |
David Luu
Member
Username: unix1111
Post Number: 6
Registered: 10-2009
| | Posted on Tuesday, November 10, 2009 - 05:27 pm: |
|
Thank you all for the replies. Sounds like I've got some work to do in the spring 2010, replacing the thermostat and impeller. Also going to check the port riser for any restriction.
David |
