darobinson23322

I have a 2002 Velocity VR1 with a 2004 496 HO. The boat is new to me. Two weeks ago had the impeller replaced and was told the impeller is pumping good. Took the boat out for the first time and it ran decent - temp was 160-165. One week later took the boat out and it started to overheat (190) as I was leaving the dock. Also, appeared to be pushing some steam. Brought the bought back to the dock, let it sit for about 30 minutes, started the boat, no alarm and idled out of the no wake zone temp around 160. Brought the boat up on plane and it started creeping back up to 190. Put the boat on the trailer. Initially thinking thermostat....any thoughts?

mr3dman

you are going to have to check your block heat exchanger and oil cooler to see if there are pieces of the impeller blocking the raw water cooling. It doesn't sound like a Tstat prob

darobinson23322

Thanks, I'll start doing that now....this is a little different from my old 4.3LX!

Randy Nielsen

iTrader: (4)

You can take the output hose off of the sea pump & the inlet hose off of the heat exchanger. Put a hose on the inlet hose to back flush the line, I had to do that a couple of times to clean out the p/s & oil coolers. That's easier than crawling around trying to get to the coolers. If the problem persists I would look into a sea strainer. Randy

darobinson23322

No obstructions in the oil cooler. I guess its time to start removing the heat exchanger.

darobinson23322

I'll try the back flush before I pull the heat exchanger. Ok, here's where you know I'm new to this type of boat engine. I'm not 100% sure I have a sea strainer.

Randy Nielsen

iTrader: (4)

What kind of shape was the waterpump housing in? they have a problem with galling out the ends & losing pressure. The p/s cooler is behind the engine & is the first cooler water goes through, then the oil cooler, and finally the heat exchanger. If you have any blockage the p/s cooler is where I would look but is the hardest to get to. That is why I suggested back flushing the line. The heat exchanger has bigger holes inside so chances are that is not where the problem is. Ask whoever installed the impeller what the housing looked like. A strainer would be installed on the inlet side of the pump & is usually easy to get to so it can be cleaned out. Randy

darobinson23322

Randy, thank you for your response. I was told the housing was ok, but i did not see it. I pulled the hoses off the p/s cooler and oil cooler I did not see any blockage in either.I will still try to back flush tomorrow. I've seen pictures of the sea strainer, but I do not see one on my boat. I'll keep looking. I may just replace the housing and impeller myself so I can rule out that part. He did say it had good water pressure and infact we ran it with no issues for 30 minute in the lake and about 1 hour on lake allatoona when I got home with no issue. It was the third time we took it out and I did notice some steam (more than what I'd seen before). But it started overheating while at idle heading out of the no wake zone.
Thanks again, Don

Randy Nielsen

iTrader: (4)

Interested to know what you find. Randy

darobinson23322

I back flushed and noticed no debris. I'm going to change the impellar. See if that helps.