Logo
FULL SITE MENU

1987 Supra 351w put pump in backwards over heated put pump in correct runs hot at idle now

G

gpod

New member
First sorry for long story but working on this for a week. Yep I did it put pump upside down. Owned this boat since new 1987 have put 3-4 impellers in it over the years but this year took pump out of boat to clean it & put new impeller in it on work bench. Put pump back in a few days later thought it was correct. Put hose to it in back yard. Did tune up, set timing, check all hose connects & temp of motor stayed at 150deg. (this boat always stayed at 150-160deg. at idle or cursing) ran 10-15 min. in back yard. Put in lake wife got out into lake 5 min. high temp alarm went off about 225deg. she turned it off called me said only 100yrd from dock nobody on lake to tow her & wind picking up I said ok idle it in. Well she was in wrong canal took about 5 min. at idle to get to dock. When she got to dock Temp. on gauge 200deg. boat running good. Shut it down let stand till cool took raw water pump off (sherwood G20) impeller shredded. Got new impeller boat store said pump in upside down ( on supras small screw on side of pump toward motor) & check for impeller parts. Put 2end impeller in took boat out 10min. at idle 150deg.- get up to 30mph 155deg.- slow down to idle temp rise to 170deg.- back to 30mph temp down to 155deg. Pulled pump thought I got all the impeller parts out but no some pieces stuck in intake of raw water pump. Ok clean pump out flush all hoses put pump back on idle 150deg.- 30mph 155deg.- back to idle 180deg.- back to 30mph 155deg. pulled thermostat ran 10deg. cooler at 30mph. Thought I burnt up 2end impeller, put 3rd impeller & new thermostat in triple check hoses & connections, trans cooler all ok, back pressure with garden hose from raw water pump output hose that connects to thermo housing, back to water pickup under boat a little leak at raw pump (screw on its side) tightened that leak stopped. Test boat same temp readings 150-155deg. at idle & 30/40mph- then slow to idle temp goes up to 170-180deg.- put in neutral rev engine to 1500rpm temp back down to 155deg. in less than 1min. Checked oil no water, boat starts & runs great hot or cold have been skiing & tubing with it over the weekend same temps as sentence above, pulled thermo to run a little cooler. Took off the supra trap exhaust baffles & cleaned them nothing bad there no steam out exhaust. When I pull output hose off of raw pump & put in bilge then crank engine no water at first then a small 1/4" stream of water comes out also when I start engine rev to 1000rpm same amount of water output was told it should be allot of water pouring out of that hose. Could it be the pump is burnt up took it a part looks ok. Please any ideas.
 
You'll need to retreive all of the impeller pieces.

Follow the sea water path down-stream of the pump, and remove everything until you find all of the pieces.
These may restrict the sea water flow if not fully retreived.

Once in a while these pieces will even make it up-stream.... so check this side also.

Lots of work...... but this must be done.
.
 
Thanks for the reply. Last night took all hoses off intake side of raw water pump had friend put hand on water intake pipe from the hull to stop water flowing into boat. All hoses clean. Found some small cracks at hose clamp area in hose that runs from water pick up in hull to trans cooler taped them with electricial tape as a temp. fix. Then put vaseline on all the hose connections to seal up any air leaks. Temperatures in engine stayed low for 2 ski runs then after 3rd ski run temp. went back up to 170deg. at idle when I speed up to 5-10mph temp. back down to 150deg. I did put a new 1" hose from the ouput side of trans cooler to inlet of raw water pump before I put boat in this spring hose felt stiffer then old one mabe to stiff to let the hose clamps get a good seal. Tonight will try vaseline on that hose only to see if temps. get better.
 
Update. Pulled thermostat housing & all hoses off pushed a 1/4" plastic hose through all no blockages. Called Supra dealer he got the raw water from PCM he said all things point to the raw pump picked it up for $425.00. My 1987 old raw pump the housing & cover plate were wore out & the 3rd impeller was cracked & had a very small grove in it that came from the small screw on the side of the pump that holds the cam in place I had a leak there and tightened it up that put the end of the screw into the impeller. Seams that all these factors caused the raw water pump not to create a good vacuum to pull water at low RPM. Put new raw water pump on Friday 7/22/11 w/o thermo temps under 150deg. all day skiing & tubing. Today 7/25/11 will put thermostat back in a hope it stays at 150deg. like it was before last year.
 
Back
Top