135 Hino overheating-gctid816661

[Guest]

I have a 3218 motor yacht with 135 hinos. Last week my port engine overheated on the way back to the marina so I shut it down and the strainer was full of sea grass.

Since then I cleaned out the strainer, changed the impeller, changed the oil checked the belt but it still heats up to 200 . I'm suspecting the heat exchanger , riser or thermostat. Is there any quick fix? Also there is a bleed fitting beside the riser. Should be bleeding air out of the cooling system while it's running?

[Pcpete]

Your raw water intake could still be clogged with sea grass. At least that's my first reaction. Did you have any grass in the pump? No need to bleed anything after the pump, and its self priming. Were it me, I'd be looking for a safe way to back flush the raw water intake.

[smitty477]

"Pcpete" post=816683 wrote:
Your raw water intake could still be clogged with sea grass. At least that's my first reaction. Did you have any grass in the pump? No need to bleed anything after the pump, and its self priming. Were it me, I'd be looking for a safe way to back flush the raw water intake.

+1 - sounds just like a raw water flow issue. If you must mess with the thermostats please note they are dual blade designs and repacking them with the wrong units will cause real problems. Best to work through the water flow issues until you are 100% sure that is not the problem.

[Guest]

After closing the seacock I'm going to remove some raw water hoses to see what's clogged. I squeezed the hose coming off the heat exchanger (stern) and it felt like something was in there.

[ALASKAN_ADVENTURER]

been there done that twice, if your cap on the screen intake is or can suck air your brand new pump will not do its job, may need a new cork gasket between your glass and cap.

[IslandHop]

Don't forget to check your transmission cooler for clog as well

[diveguy]

You may need to check the intake on the hull as well in case something is restricting the flow.

[Guest]

I think I've found the problem. Seagrass clogging the intake. Unfortunately it also destroyed my new impeller.


Attached files

[Guest]

I didn't realize there should be a gasket there, it's definitely missing.

[mmichellich]

"SeaQuest" post=816801 wrote:
I didn't realize there should be a gasket there, it's definitely missing.

It is better to replace the old cork gasket with a new rubber gasket if you can find one. If you have not had a gasket you are not pumping enough water and potentially destroying impellers.

[Guest]

Actually there is a gasket but it wasn't noticeable.

I might make my own gasket.