High Speed overheat

gearshift46

I have a "new" Bobcat 5.8 Bravo Magnum in my 1992 Rinker Fiesta V (installed Nov 2017 w/ 43 Hours on it) No complaints until last week when I noticed at high speed it climbs from 160 degrees to 180-190 at high speed. Backed off once it hit 190. As soon as I back off it goes back to 160-165. When I checked the engine, the starboard riser and manifold were much hotter than the port side of engine. This condition seemed to come out of nowhere. I'm assuming that I sucked something up that is blocking the raw water from exiting the boat on stbd side. 
Like to know if anyone can suggest a simple troubleshooting procedure before I send this into the Marine mechanic at $150.00/ hour.

Cableguy Greg

What drive do you have coupled to your engine? I am thinking the raw water impeller is going bad.

gearshift46

Bravo 11. Keep in mind that the Starboard side is much hotter than the port. You can lay your hands on the port side manifold and riser even after 190 degrees on gauge.

reneechris14

You can flush the system. When the impeller starts to get weak the water will take the easier way. Closed cool? Or raw water cooled?

gearshift46

Raw water cooled

jhofmann

When is the last time you changed the waterpump from the outdrive? A number of people say every other they should be done. 

jhofmann

I went 4 years before I had any issues. When I pulled out the rubber impeller, most of the vanes were gone. Luckily none got lodged anywhere, and a new impeller solved the problem.

gearshift46

engine is new Nov 2017......I have a Bravo 2. Waterpump for raw water is on the bottom of engine starboard. I guess it's worth the check however, not in the habit of changing impeller every 3-4 months.

GMSLITHO

Could be the intake hose  

gearshift46

Thanks...I've got a list of things to check. So darn hot here for the next few days I would expire working on the boat in this heat.

Michael T

with @gearshift46 on that one. Easy to start with the hose as it can easily collapse under draw if it has gotten soft/spongy causing it to severley restrict the water flow.

gearshift46

Thanks, I'll add that to the long list. The first thing I checked was the easiest (and the scariest)....no water in the oil!

gearshift46

Ok guys...there was not a whole lot of summer left, so I gave the boat to my mechanic. First, the raw water pump was replaced because the pump body was scored, (sucked up some gravel) Sea trial showed overheat again over 2K. Pulled outdrive after backflush showed little water coming out. Hose going to pump (outdrive side) loaded with mussels. Cleaned this out.Removed lower unit.....loaded with mussels.....cleaned all this out. hose in lower unit was collapsed, replaced this hose. Picked up boat today. All is good! $1500 later.

Liberty44140

Glad it’s all taken care of! Thanks for posting the outcome 

Dream_Inn

great to hear it's all fixed and you can still enjoy some good boating left!

gearshift46

I thank all of you for your suggestions. Had a great time on the water yesterday and today. Perfect weather!

halifax212

$1500 and not even a good feed of mussels out of the deal ha

gearshift46

"BOAT"...break out another thousand...+$500