60/40 Jet low-flow "pee-hole"

[tboydva]

First post in the Merc forum here! Aside from my '66 Merc 65 HP (which died in 1989), I've had mostly OMC engines. Last month, I finally got my river jet boat which has a 2004 60/40 Merc Jet. The PO was an older gentleman, and from what I can tell, he didn't (and probably didn't have to do) too much maintenance. I did a compression check before purchasing and all three cylinders were dead on 120 psi. A visual inspection at the pistons (and the 96 hours on the gauge) led me to believe the engine was solid - and it has been.

After my last outing, I noticed the water stream coming from the pee-hole was very weak (during my flush). Seemed odd, so I gently ran up the rpms a bit, and it increased some, but I check it often and before this time, it had been shooting out. I had no problems or alarms during the outing. So, I figured either it was a bad water pump (6 years - a reasonable scenario), or worse, perhaps some of the silt in the river is clogging passages. I run my other boat (regular prop) in the lower Potomac which is like chocolate milk and have never had any water jacket issues before... The upper Potomac and Shenandoah are crystal clear by comparison!

I pulled the water pump and it really looks very good. It's soft and springs back easily. There is some scoring on the stainless plate, but not what I'd call really bad. So now, where do I go with the troubleshooting? I'm planning on servicing the pump with a new impeller and perhaps plate (if it can't be smoothed down). I've searched here as best I can and here's the only thread I found on silt in the block: http://forums.iboats.com/showthread.php?p=2543949

Unlike my OMC motor which has a head and exhaust cover plate, the Merc seems to have a fully cast cylinder. The OEM service manual shows water flow and it appears that the thermostat could be pulled to gain some visual access...

I'm sure there's a thread I missed, but can someone point me to a next logical troubleshooting step? I'm praying perhaps the hose for the pee-stream line is clogged or something simple, but I like to have my machinery running like a top before hitting the water, so even without an overheat or anything, I'd like to play it safe!

Thanks in advance for any help.

 

[jerryjerry05]

Re: 60/40 Jet low-flow "pee-hole"

6 years on an impeller is pushing it way past it's due date.Every other year is the longest.
Take some weedeater line and push it through the hole.Or take it apart and see what you can find.
In my neighbors outboard I found about 30 little paper wasp nests,about an inch and a half of paper come out when I took it apart.
I recently bought a boat with twin 85 Forces(no peehole).I started them up in the yard and it shot about 2# of sandy/mud from a BUNCH of mud daubers. It was really packed in there.J

 

[tboydva]

Re: 60/40 Jet low-flow "pee-hole"

Jerry, thanks! My next step is to work backwards from the pee-hole and hope I find something... Water pump kit is on the way. Because the stream was so strong before, I'm hoping that any potential blockage isn't "too deep" in the powerhead that I can't flush it out. Right now, I favor the older OMC design of an exhaust cover plate (even though I've had to have broken bolts milled out!). I will say this 2004 Merc is a beast on the water though!

A friend has a Honda 4-stroke and he has constant mud dauber issues. He was saying the Honda design accentuates the issue. The PO for my boat kept it in a pole-barn, so it was exposed to insects. I've kept it in my garage so I'm thinking it's something else - but whatever - as long as I can fix it! Fishing in our mid-Eastern rivers is hot right now!

Edit - I pulled the pee-tube and it's clean - and if I blow in it, I can hear it clearly (with no obstructions) into the exhaust jacket. I pulled off the thermostat cover. The thermostat had some grass in it, but the jacket looks as clean as I can imagine (fresh water only motor):

I'm hoping it's just a fluke at this point. Perhaps there's a passageway in an inaccessible area, but I'm going to force water "down" through the passageways I have access to and hope if there is, I can flush it out!