My first

[CHANCE1234]

I thought it was the transducer that determined how well you mark the bottom? I will be going with the furuno transucer made by the Japenese. It is the dual freq ducer 50/200. My father has the exact setup on his lobster boat which he has taken tuna and cod fishing.

[Bigshrimpin]

The 667 is only 300watts . . .

This is a decent overview for fishfinder info:
http://www.cabelas.com/information/c...onarGuide.html

I thought I posted these yesterday, but I guess not. You might appreciate these charts if you haven't seen them already.

Chart of Stellwagen Marine Sanctuary:
http://pubs.usgs.gov/of/of00-410/pdf/topo.pdf

Lat/Long of all the spots on chart:
http://pubs.usgs.gov/of/of00-410/names/frames.htm

[CHANCE1234]

Well, she is just about done (for this year) The transducer is installed in the new block that I built and all that is left is to wire it to the machine which I hope will be done this week. After that I need to tow it back to Metan marine for some fine tuning and to run in to make sure everything is good. Soon after that you will see some pictures of her in the water. I can't wait, and I hear the squid and some small keepers are showing up in the sound. Wish i had some more pictures but not much as changed physicaly sine the last pics. Hope to have some underway pictures soon.

[CHANCE1234]

Alright so this is how it went. Put the boat in the water for the first time on friday. She fired right up. GREAT!! 5 minutes later the was coolant spraying all over the place, she had overheated in under 5 minutes. Sea Suction was open, so i suspected the impeller, or thermostat. I pulled the thermostat first becuase that was easy. It was fine. Next I wresteled with the impeller. Miles and any other inboard guys may know how much of a pain in the arse it is to replace that thing with no room to work. That took roughly 5 hours to take out, and now being sunday i had to try every marina on the cape to find the right impeller. Finnaly i had it, 2 hours later she was installed and ready for the water again. Now back at the ramp, fired her up and about 5 minutes later the the temp was climbing into the red, so i shut it down for the weekend. The only thing i can think of is that the old impeller pieces are clogging the lines. Are there any other possiblities? It is a very simple raw water system, what am i missing. Frustraionnnnnnnnnnnnnn!!!!! Please help. She did look good in the water, but that is about all the nice things i can say about her right now. Why would the impeller burn out first time in the water but last year when i bought her and seatriled everything was fine. the only thing i can think off is from the time i seatrialered her to the time i actully picked her up was about 3 weeks. I don't know if something happened from seatrail to delivery.

[Abe's Rocket]

is it pumping water? do you have a sea strainer?

you could have a bad heat exchanger or an air lock in your coolant system...

[oldfielder]

Definitely open heat exchanger and see if those pesky chunks made it there. It doesn't take much at all to fry that impeller. Might be a good time to check the risers for blockage. Not fun but the more I find out the more I see that they are another preventive maintenance item.
Great source of info for the mercruisers is boater ed forum. I think it's part of boatfix.com. Very helpful bunch there-kinda like here.
Goodluck,
Doug

[Miles Offshore]

hey Dude- probably one of 3 things- answer a couple of questions for me-
Is your raw water pump the johnson type that is attached to your flywheel or the stand alone type??
a) if it is attached to your flywheel (johnson kind) what happens is there can be grooves put into the brass cover of it and you can replace impellars all day and it still wont work. When the motor is cool just remove the discharge side of the pump, start her up for a couple of seconds and see if she is pumping. If not just cut your loses anbd buy a new pump. Been there done that.
b)Transmission cooler- pull the inlet side hose off the cooler and stick your finger in the cooler and see if there is any trash - the area is pretty small and it doesnt take much trash to clog it up.
c) this is what i really think your problem was and you probably burnt up your impellar because of it. You probably got an airlock via your seawater strainer. -( verify it by visually seeing it pump like i described earlier- pulling the discharge hose (be sure your bilge pump is working,lol). With the motor RUNNING, open up your strainer and you should see flow. Now close it- thats it- what happens is if you open it with the motor not running it will cause that vapor lock when you start it up. Thats why you need to open then close it while the motor is running. I doubt the heat exchanger is the main problem- it could be causing some but the little oil cooler/tranny heat exchanger is a good possibility. Check these things out and let me know- craig

[CHANCE1234]

Thanks miles, that is all awesome info. I have the johnson type and i will be sure to check all of the areas you have suggested. If it is just air locked should i bother to try to find the pieces of the old impeller? Also since i put in the new impeller and it still overheated, what are the chances that the new impeller is now junk??

[Miles Offshore]

yes- try to find and remove the old pieces- should be in heat x-changer,-- hopefully pieces never made it to your risers.- and again if that cover on the johnson pump is grooved dont even bother with a new impellar- just buy and replace the pump- it only runs around 150 for a replacement-generic and you wont have to worry about it. good luck- let us know-

[CHANCE1234]

miles, when you say cover on the pump is grooved. I have a stainless looking real thin piece of metal that allows the bolts to go through it and into the impeller housing. Is that the cover you are talking about, or is it something else. And when you say to possibly replace the pump do you mean the housing and shaft assembly that the impeller sits in? Thanks for any clarification. I am getting better with the mechanical stuff, but still consider myself an ametuer. If i take something apart i can put it back to gether but some of the proper mechanical terminology is still lacking. Thanks again.