Runnin Hot.

[charlie_the_tuna]

lately when i idle the temp starts to crawl up but drops back down when i go into gear.
i'm thinkin a stuck thermostat.

ferm?

spare?

[spareparts]

you've got an I/O right? better start with an impeller. I've been working on I/Os for 22 years, I can count on my hands the number of bad I/O thermostats I've found(true marine thermostats, not auto thermostats installed in a boat)

[THEFERMANATOR]

Impeller sounds about right, or a problem with the check balls on the T-stat's not sealing. Your alpha outdrives impeller doesn't move as much water into the block at idle as the circulating pump will pump out when the T-stat opens. So the temp will climb up as the water is pumped out and air gets sucked back through the manifoilds. Fairly common issue with the ALPHA's. Do the impeller first to make sure that is right, wouldn't be a bad isea to do the whole kit. If that doesn't do it get a replacement check ball kit. I went through this on that SEARAY last year, ran dead on at 160 when running but would climb up to 180 at low idle. Come up to 800+ RPM's and it would drop back instantly.

[charlie_the_tuna]

just did the impeller last season.
cant have 50 hours on it.
sh!t.

[THEFERMANATOR]

Impellers are considered to be an annual maintence item, espescially up north where they get hard from the cold during winter. Also check the check balls on the T-stat housing while your there.

[charlie_the_tuna]

wait a minute, you mean the impeller in the lower unit, right?
where are these check balls?

[THEFERMANATOR]

Yep, the impeller is in the outdrive. The check balls are in the T-stat housing.

Does your housing look like this one? This is the common ALPHA style housing.

[spareparts]

when you check/replace the impeller, take a good hard look at the housing, look for any deformaties or scarring, also look at the lower part of the impeller housing(under the ss plate), make sure its not warped. If you have any doubt, replace the whole water pump assembly, its not that hard to do, just make sure you match up the right orings and gaskets if you get a new kit, they generally come with enough extra(wrong) parts to really confuse you. Also wrap a bit of electrical tape around the oring grove on the drive shaft when installing the lower water pump housing to prevent damage to the seals, remove the tape before putting the lower unit back together.