TenMile
Well-Known Member
Hey guys,
I've got something that seems to be stuck inside the raw water intake for the cooling system on my inboard. I have a Bravo III leg attached to a 5.7L MPI Horizon. Means its a belt driven water pump with a heat exchanger with circulating coolant -- impeller is new this season. Boat is currently out of town in Bamfield and I'm trying to figure out the best way to clear the intake without having to pull the boat and remove the drive.
I have a Mercmonitor on the boat which allows me to measure the cooling water pressure and coolant temperature. Boat had a "minor" overheat -- temp got to 190 degrees, alarmed -- and I stopped -- immediately temperature fell back to a normal 165. I noticed that water pressure was only 2 psi. Got to the dock, did a bunch of checking and figure I must have sucked up a weed or something. Intake vents appear to be clear from the outside. Removed the intake hose from the pump and found the water flow to be a trickle (it usually gushes out enough to be scary). Took a manual bilge pump and was able to pump water through the intake out the drive leg, and then reversed it, to suck water from outside in again. After doing that, water flowed through the intake with much greater force. Let it run for about 5 minutes into the bilge and found a 2" mussel shell (not completely sure if it was the culprit as I didn't actually see it fall out of the hose). Reconnected the hose to the pump and ran the boat and water pressure was up to 12psi for the rest of the day (I assume this is "normal" but I've never monitored the water pressure actively until now).
Next day, I found that water pressure will now only max out at about 6psi so something must still be stuck inside. The boat doesn't overheat but the temperature will creep up to about 170 degrees slowly which is a bit higher than the normal 163-165. Any other techniques on flushing crap out of an intake hose? No trailer available so this has to be done in the water. Figure if this continues my next option may be to position the boat close to shore, attach muffs, remove the intake hose and try to flush it out that way. Maybe a fish-tape or toilet snake would work??? Ideas???
I've got something that seems to be stuck inside the raw water intake for the cooling system on my inboard. I have a Bravo III leg attached to a 5.7L MPI Horizon. Means its a belt driven water pump with a heat exchanger with circulating coolant -- impeller is new this season. Boat is currently out of town in Bamfield and I'm trying to figure out the best way to clear the intake without having to pull the boat and remove the drive.
I have a Mercmonitor on the boat which allows me to measure the cooling water pressure and coolant temperature. Boat had a "minor" overheat -- temp got to 190 degrees, alarmed -- and I stopped -- immediately temperature fell back to a normal 165. I noticed that water pressure was only 2 psi. Got to the dock, did a bunch of checking and figure I must have sucked up a weed or something. Intake vents appear to be clear from the outside. Removed the intake hose from the pump and found the water flow to be a trickle (it usually gushes out enough to be scary). Took a manual bilge pump and was able to pump water through the intake out the drive leg, and then reversed it, to suck water from outside in again. After doing that, water flowed through the intake with much greater force. Let it run for about 5 minutes into the bilge and found a 2" mussel shell (not completely sure if it was the culprit as I didn't actually see it fall out of the hose). Reconnected the hose to the pump and ran the boat and water pressure was up to 12psi for the rest of the day (I assume this is "normal" but I've never monitored the water pressure actively until now).
Next day, I found that water pressure will now only max out at about 6psi so something must still be stuck inside. The boat doesn't overheat but the temperature will creep up to about 170 degrees slowly which is a bit higher than the normal 163-165. Any other techniques on flushing crap out of an intake hose? No trailer available so this has to be done in the water. Figure if this continues my next option may be to position the boat close to shore, attach muffs, remove the intake hose and try to flush it out that way. Maybe a fish-tape or toilet snake would work??? Ideas???
