Cooling/Water Intake

[lncoop]

I have a 2002 90hp Merc two stroke on a party barge. I noticed today that my water pressure wasn't what it normally is. The motor was pumping water and cooling, but the pressure just wasn't up to normal levels. I was floating in the water and started looking at it, and what I found was a little 90 degree fitting at the bottom of the LU (on the front) with a section of tubing attached to it. I've never really noticed it before, but I discovered that the end of it was crimped and a little ragged like it had been shorn or something. So my questions are:
1. Is this the cold water intake for cooling? I've never seen one like this.
2. Is it supposed to hang down in the water, or what?
3. How long is it supposed to be? It's about seven inches now. I don't know if that's normal or if it was somehow cut or something. Did just pick up the boat from the weld shop. Don't know if they might have done something.
Any insight anyone can provide regarding how this is supposed to look and work will be appreciated.

 

[latin monkey]

Re: Cooling/Water Intake

does your speedometer work?

 

[olsenk514]

Re: Cooling/Water Intake

That fitting is the output to your speedometer pitot tube. If your speedo is working correctly, then it should be fine. The water intake is on the front of the lower unit. There's about 8 or 10 holes drilled vertically.

When's the last time you changed your water pump? A failing pump could have low water pressure. Even 5 seconds of running out of water can soften the impellers on a water pump

 

[lncoop]

Re: Cooling/Water Intake

Thanks everyone. I don't have a speedo, so I guess the condition of that tube doesn't matter? It may sound strange, but the PSI were generally higher when I ran the motor at lower RPMs today. Is that consistent with a failing impeller? I've been running it all summer and it's had really good water pressure every trip. It just started doing this today. Do I just need to go ahead and replace the impeller?

 

[latin monkey]

Re: Cooling/Water Intake

if it hasnt been changed in a while then yes. its good insurance and you can see the condition of the old one. i usually use some vaseline when installing the impeller, it makes it easier and washes out with no problems

 

[olsenk514]

Re: Cooling/Water Intake

Yes...I change mine every year. It doesn't necessarily need to be done if it's pumping water but like the last post says...it's good insurance, and it's relatively cheap. From my experience, the pressure will drop slightly when going to higher rpms. Just curious...what psi readings are you getting?

 

[lncoop]

Re: Cooling/Water Intake

When I was going fairly slow, say under 3500 RPMs, the needle was bouncing between 8 and 10, staying closer to 8. At higher RPMs, up to 5K which is WOT on that rig, I was getting 6K to 8K, staying closer to 8K which, based on my limited experience with that motor, is low. It normally has a really strong stream.

 

[lncoop]

Re: Cooling/Water Intake

I had some welding done on the toons a week and a half ago. This is the first time I've used it since then. Is it possible the heat from the welding could have degraded or damaged the impeller? Sounds far fetched I know, but I'm just trying to get my head around how it could be peeing like a champ one time out and weaker the next. I know it's possible, but just seems a little odd.

 

[olsenk514]

Re: Cooling/Water Intake

I don't think the impeller could have been heated up unless they did welding on your lower unit. In any case, I would change it out...It seems like that is your problem. It's possible that you picked up a little bit of sand or silt - which will wreck havoc on the impeller.

You can probably find one online for about $20-$30, and it should take about an hour to change. It's a fairly easy job.

Let us know how you make out

 

[lncoop]

Re: Cooling/Water Intake

New impeller it is. I just hope I can get it done this week. I don't have time to mess with it and I'm sure the shops will be covered up. Maybe they'll squeeze me in since it'll be a quick couple hundred bucks for 'em. Some times you just gotta spend the money. You know what they say B.O.A.T. stands for. Thanks for the advice.