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2biguns
06-16-2003, 08:30 AM
My buddy who has the 253 Cobalt for sale (see "Other Boats for Sale"--fresh paint going on Cobalt as we speak) got a nice surprise from his wife. She got tired of hearing him whine about how much he wanted to buy the 271 Formula so she borrowed the money and bought it for him. Now he's a 2 boat owner.

QUESTION: What's the proper operating temperature for a 502 Mag EFI? My carbureted 454's run between 115 & 120. I "borrowed" his boat Saturday to see how it runs and when the temp hit 185 I rushed it back home and put it back on the lift.

Do I need to clear out a block of time Saturday am to replace his impeller?

Donzigo
06-16-2003, 08:46 AM
Steve, my carbed 454's run 160 every day. My guess is that 185 might be about right for the 502's. Your 454's run much colder than mine; but, then again, what's your water temp going into the boat. This Florida salt water is probably hotter. I know Ihaven't helped you at all; but, I needed the practice typing.

How's the 29 running? I was disappointed in your getting rid of the home on wheels. I showed everybody I know, a picture of you sitting on the porch, one of the funniest picture I have ever seen on the web......LOL. FYI: I know it wasn't you in the picture)

2biguns
06-16-2003, 09:03 AM
We had our one-year anniversary with the new engines in April. I believe we put about 120 hours on them last year without a single hitch. You're right about the water temp. Smith Lake is an extremely deep (250' to 350' in some places) waterway with very cool water. I had a 502 mag (carb) engine in 22' Stryker a few years ago and it ran the same temp as my current engines. I assume that the EFI engines run much warmer.

Yes, it's going to be a sad day when we leave the tin can on the hill. I don't think you can claim to be a true southerner until you experience certain things in life including living through tornado season while living in a trailer. :D Amy and I made it through 2 tornado seasons (last year we were actually hit by one--she and I and our 3 dogs rode it out in my truck at the foot of the hill and the truck almost flipped over, but that's another story).

MOP
06-16-2003, 01:18 PM
BB or SB raw water cooled 160 -170 185 is to hot. If the engine has closed cooling then 185 is fine.

wytmike
06-16-2003, 01:40 PM
Our 2001 233 Cobalt has the 502 Magnum in it. It runs 175-180 with raw water cooling. Water Temp in Tahoe is ow 60's

2biguns
06-16-2003, 01:41 PM
Raw water cooled so me thinks it's time to check the impeller.

If it has to be done, I'd much rather replace it while the boat is sitting on the lift and COOL than to let it overheat in the middle of the lake and sweat my rather large posterior off fussing with a hot engine.

Bryan Tuvell 33ZX
06-16-2003, 02:28 PM
My 502 ran 180 all day long (since new) with standard manifolds/risers, runs 170 with SMarine manifolds. Stat is a 160 per Merc (when hot, 165ish at idle) . She will alarm out at 220.

On the impellor, don't just replace the impellor, if there is scratches or grooves in the housing replace it also. Squirt it with a little WD40 to help get the new impellor in the housing so it won't be burning rubber it's first few turns trying to get the water.

We usually do the housing and impellor at least once a season on the 502 and at every spring as a maitenance item.
Best of luck to you.
Bryan

PS, we carry a full spare kit in the boat at all times.