gunnarb

Hi everyone, I finally have my first boat over 15 ft long. Not sure if it qualifies as an off shore or not but we just took our first run in it yesterday and I have a few questions.

My new old boat is a 1987 Wellcraft Nova III with twin 260 HP Mercruisers and alpha 1 drives. I've had it for over a week and made sure all my fluids were clean and the drives were greased up, along with a ton of cleaning and a bunch of little repairs that I wanted to do.

I noticed while idleing out of the canal that my startboard engine went up to the 240 mark. Its a good 20 minute ride out but I was suprised it got that hot. I bumped the throttle up a notch and she quickly came back down to the 160 range.

The port engine stayed around 140 the whole day idle or full power. I had water coming from both exhausts - looked of equal amont. Question is what should I look at first to get the starboard engine operating at the proper temp? Is this normal for an older boat?

S-side temp was fine while cruising or wide open. Thermostats are supposedly 160's.


The other annoying thing was my depth sounder reading all over the place. It was steady during the sea trial. Could bumping it on the trailer cause it to read whacky? Should I just buy a new one?

I'll start there. Hopefully not too stupid of questions? Thanks for all of your help in advance. By the other threads out here I can tell there's a great bunch of people out here.

Gunnarb

ChristianGott

hi.
congrats on the boat...i'm guessing either a thermostat that's not opening fully or a worn water pump impeller...both easy fixes...good luck
c

gunnarb

Thanks. What temp thermostats do you guys run in the 260's?

ChristianGott

i run 140's i think that's the 350 mag spec....temps average 150-160....
do you have the t-stat housing that has the check balls on springs?...if so, maybe there's just a bit of corrosion?
equal water flow from the pipes might be due to bypasses, somewhere there might be a restriction....some spare time and cleaning of interior lines might help...my housings and related parts are 22 years old, been disassembled and cleaned out twice in the 7 years i've owned them...check the gimbal hoses too...take the time to start at one end and move to the other....good news is that cars run at higher temps, so 200 for a short time isn't going to bust stuff up....
c

gunnarb

Thanks for the tip. It does have the check balls in it. I'm going to change the impellers and pumps since they haven't been done in a while. If that doesn't do it I'll start cleaning out all of the hoses and other cooling areas like you suggested.

jbraun2828

It's the impeller. When your up on plane it forces water through to bring temp down but not enough volume at idle. My motors run at 180 degrees. Good luck.