monstaaa

with the imco lower the intake port is very big, and needs to be machined to broaden the area so we can put a recessed mini grating over it. this has dropped the p.s.i significantly. on a 38 fountain that runs 104, this is exactly what we did, because when the lower took a crap we replaced it with a new one. on the first test the water pressure gauge pegged then blew. difference in the lowers was one new, and one machined as mentioned above. machining solved problem. dropped p.s.i to 20 lbs

chip12345

Update: Problem fixed... Changed exhaust to stellings and had new tips made... Water pressure is perfect. Must have had a collapsed tip not letting water exit the boat.

Mr Gadgets

Monstaaa,
How about some pics of that grating?? Would love to see it..

Thanks
Dick

monstaaa

try to post sunday

Brock

What about too low of water pressure?? Stuck in Havasu with one motor running hot.
Gauge reads 0 on water pressure and engine doesn't heat up until cruising at about 60 or more for 5 minutes.
97 42 Lightning with merc 500 carbed motors.
I pulled the t-stat to see if it was stuck and that made no difference.
I checked the impeller and it looked perfect.
I hooked a garden hose up to the impeller imput hose and ran water backwards out the drive to make sure it wasn't plugged and it looked good.
I ran the motor with the hose that supplys water to the waterpump and it had a pretty good flow of water.... so the impeller is working.
Any ideas? I'm here 4 days with 4 people and we cant' cruise around!

Pwrbt33

If its a Fountain you say, make sure the flush valves on the transom are closed and the water intake valves are open all the way. Also make sure the water pocket cover at the transom isnt smashed closed. Do you run your boat in salt water? I have also seen the coating on the gil manifols come off internally and clog up the water outlet ports to the risers.

John

Brock

Valves are good. Has been in salt water. What are the water pocket covers?

Pwrbt33

The water pocket covers are the 45 degree elbows that the incoming water hose conects to on the inside of the transom. If a boat is used in salt water all its life these hoses are sometimes known for collapsing internally. There is a small wedge on the inside that holds the hose in the housing as it comes threw the transom assembly. Follow the water hose down to the transom assembly. Use a 1/4" wrachet with a 7/16" socket and remove the 2 bolts. Look inside the hose as it comes threw the assembly. It should be open. About the size of your ring finger. If it looks crushed or small as a pencil, the water hose will then need to be removed and all the salt and corrosion will need to be removed and a new wedge installed along with a new water pocket cover gasket. If all this is fine, keep checking for your over heat problem. Does the boat float or do you keep it on a high and dry?

If you need more info feel free to call my cell or the shop.

John
c-443-786-2309
s-410-827-0200 x-0 for service

Brock

Thanks, I'll check that hose before we put it back in the water. I replaced the water pump and backflushed everything as good as possible. Waterpump impeller looked ok, so that wasn't it, but I had it off and it had seeped out the weep hole previously.... so I replaced it. I'm not expecting great results tomorrow.
The check-valves to the exhaust looked like they were ok also.
I keep it out of the water and very dry on the side of my buddies house here in Havasu... that makes it really suck when we fly down here, pay $1000 for a room and work on it all weekend.
I appreciate your help.

BadDog

Jaybird,
Did you meand to say that the dump valve should be afer the water pump and first cooler? If you place it between the pump and first cooler you are reducing the amount of water that the cooler will see. You want as much water to pass through the cooler as possible.