Low/no water pressure / no temperature reading

[Bill L]

I bought a 2003 donzi classic w/ a 350 mpi / bravo drive recently. My choice would have been a 6.2 but the price as well as the condition of this boat made me go with this one.

Anyway, when I took a test drive the seller ended up in a sand bar. Took a while to get out and the boat started to over heat but after cleaning out the outdrive it seemed to be fine.

Ever since I had the boat the water pressure has been low but no overheating. Thought it might be the guage/sending unit. Last time I had it out the water pressure guage read zero and the temperature guage read zero. I think it may be related to the sand bar but am not sure.

I read about a sea strainer and thought I could clean it out but am not sure the boat has one or where it is located.

Does anyone know if my boat has a sea strainer and where it is located in the engine compartment?

Also, does anyone have any thoughts as to what my problem might be? Seawater pump/impeller?

Thanks,

Bill

[Mr X]

Bill, your boat does not have a sea strainer. It is related to the sand bar incident.
The impellor is damaged AND the engine cooling system and block are full of sand. Unless you are familure with the cooling system and good with tools and mechinacal work it should go to an authorised service center for a full flush out of all the sand.

[MOP]

Without looking at your rig all any of us can do is guess, if you have a strainer it should be very obvious. There would be a 1-1/4" hose coming from the transom shield running into and out of the other side of the strainer then going to the thermostat housing. You more then likely have sand and mud in the block and oil cooler, sand can eat an impeller fair quick. I would check out the temp thing first, first see if the gauge is working right, look for a tan wire it is connected to the temp sender by the thermostat housing. Try turning the key on and grounding the wire at the sender, the dash gauge should pin showing hot. I would try to get the sand/mud out by running on the muffs, get it started and take "one" block drain plug out. You may need to probe it with a wire to get it flowing, once you get a good steady stream put that plug in and go tot he other side and repeat the process. Lastly you need to flush out the oil cooler by removing its plug, that should get rid of most of it. As to the low pressure issue you need to find where the pressure gauge is hooked up at the block, disconnect there and also behind the dash. The tube needs to blown out from the dash end, then while it is still disconnected start the engine on the muffs again to flush out the orifice at the block. Hopefully this will help you out, I would install a new impeller when done/clean!

Phil

[Pismo]

Does it still run? Are you driving it? If it is not overheating then it is getting enough water flow. The sending units may have been trashed by the sand. Flush, flush, flush, get some new sensors. Water pressure gauge?? Rare to have one of those, very rare.

[yeller]

Water pressure gauge?? Rare to have one of those, very rare.Standard on the newer 22's. My guess is since they switched to the monster gauge.

[Bill L]

Thanks guys. I really appreciate the input.

It still runs, just making me nervous. Doesn't seem hot but should not have run it as much as I did.

Before I knew I had a problem it would run around 60 mph and only rev to 4000-4050 rpm (second time out). Also didn't seem very peppy. I looked through the manual and saw that mercruiser runs some "guardian" system that will only allow 90% throttle if certain conditions occur, one being low water pressure.