Sea water intake hose coupler?

[weekend warrior]

I have a 1994 sea ray 240 with a McM 454, bravo 1. I've been chasing an overheating issue for a while. I replaced the impeller and test at with in the last month. The boat sat for 2 years due to medical issues.

The engine ran at 180-190 on muffs and through a Flush tee in between the outdrive and sea water pump.

I finally attempted to drop the boat in Friday night and it shot up to 220 (pinned)

Back on the trailer I hooked up a hose to the tee and had no water to the test at housing. I back flushed the cooler and found my impeller fins. I pulled the pump housing to find a stub of an impeller.

When I hook up the muffs, I get no water to the pump. I'm assuming, even, on muffs with engine off, I should get some water flow up there.

I would like to bypass the tee in the intake hose. Can I use a nylon barbed connector to bypass the tee? I'm a little worried about the connector due to flow restrictions.

My other option is the perks flush pro but I want to try and wrap it up by tomorrow morning.

Also, I'm concerned as to what fried the impeller. I'm counting on the facts that I hope the tee somehow failed and caused the impeller issue.

Btw, the temp seemed ok on the tee connector in the driveway. I little high at 180-190

Any quick thought would be appreciated.

Thanks in advance.

 

[weekend warrior]

Re: Sea water intake hose coupler?

Sorry, just noticed the auto correct. It's a mercruiser (McM)

 

[Don S]

Re: Sea water intake hose coupler?

How old was the impeller? What shape was the pump housing in? You can use a nylon fitting to replace the tee.

 

[weekend warrior]

Re: Sea water intake hose coupler?

The impeller was about a month old and was never used in the water yet. I replaced it bc the boat sat for 2 years on the trailer. The one I replaced was used for one season and looked brand new.

The housing looked fine to me and the wear plate looked brand new when I pulled it today. I tried to get an impeller kit today but could only get a kit with a new one piece housing. I will replace the whole thing tomorrow as well as remove the tee and put in a coupler for now.

My fear is I don't now what shredded the impeller. When I run a hose though the intake hose ( backwards towards the drive) the water flows out the drive intake hose with gusto.

I'm confused as to what fries an impeller. My impression is that the way the impeller fries is because there is no water flowing through it.

 

[Pete104]

Re: Sea water intake hose coupler?

They can be a devil to prime. Grease the housing & impeller when you put it together. Then, don't start it until you water up the intake hose.
You may have to use duct tape on the muffs to get them sealed enough to force water uphill.

 

[weekend warrior]

Re: Sea water intake hose coupler?

That's another point of confusion. I've been told not to use grease. Use dish soap and water. What are your thoughts on that? The seloc (another point of debate) says grease but the merc manual says soapy water. I tend to go by merc over seloc most of the time. I am open to reasonable opinions on the grease vs soap. You guys are way more experienced than I am.

All the impellers I have put in have been with soap based on the manual.

 

[Don S]

Re: Sea water intake hose coupler?

Petroleum products can damage impellers. Dish liquid works great.

 

[weekend warrior]

Re: Sea water intake hose coupler?

UPDATE! I replaced the impeller and housing, tstat and gasket, back flushed all hoses. I was hesitant to remove the tee because I could only find a PVC coupler at home depot. I did remove the tee and take it apart.

The tee has a large spring and cylinder that push down when pressure is sent through the hull flush fitting. I found that the cylinder was not returning to the home position and cutting the opening in half. I greased the bejesus out of it, put it back and did not use the hull fitting after that.

The engine ran at around 170 with muffs (according to the gauge). I dropped it in the bay and ran it for about 30 minutes. The temp was steady at about 180-190. I did not have my ir gun with me.

It has always seem to run in that range. Am I missing something that is letting it run that warm or is that temp ok for a 1994 engine that was allegedly rebuilt 3 years ago?

Thanks for everyone's help. Therevwere several other threads that also gave me great advice.