raw water pump

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sehord
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raw water pump

Post by sehord » Sun Apr 21, 2013 9:41 pm

Anyone have any idea as to the GPM a jabsco raw water pump on a crusader 454 (at any rmp). Chasing a warmer engine issue......
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gettaway
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Re: raw water pump

Post by gettaway » Tue Apr 23, 2013 5:35 pm

here is the flow chart for sherwood pumps, the E35 pump on the crusader engine uses the 10077 impeller, according to the chart, and depending on pulley ratios, however, at 2500 rpm pump speed, it should pump 26 gallons per minute.

http://www.sherwoodpumps.com/en-us/Prod ... rformance/
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sehord
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Re: raw water pump

Post by sehord » Tue Apr 23, 2013 5:44 pm

Thanks Scott... I havent had a chance to check them out yet, but will this weekend. Ill compare those numbers plus check my other main and see what I am actually getting everywhere. All manifolds are clean but exit flow looks weak, even with new impellers in the past 6 months.....
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Re: raw water pump

Post by Big D » Tue Apr 23, 2013 9:50 pm

If the impellers are fresh, all raw water hose clamps are tight, and no growth on the thru-hull intake, check the "U" cooler. Are the exhaust manifolds at the same temp as the other engine? Use an IR temp gun and compare temps at different points between the two engines.
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Re: raw water pump

Post by sehord » Wed Apr 24, 2013 5:48 am

I did look at the u cooler and it flows fine. I flushed it backwards first then forwards and found no debris. It has always run hotter than the other, by some degree, and I believe I have a faulty temperature sending unit as it reads that it is running over 220, while using an IR gun at the thermostat housing I am showing around 180-185.... while my Stbd main shows 155 with an IR, about a 30 degree difference.... not a huge deal except once I power it up over 3000 RPM I get a good amount of steam coming of of it (I didnt check its total temp while up and running). So I am on the hunt. I keep it on a lift so growth should not be a concern, but to be safe that was my start. I pulled the intak hose of the sea cock, checked the intake valve and ran a long screw driver through it and found no growth, then flushed the cooler and also ran some scale remover through the freshwater coolers in case some build up has occured there. However visually it appears that the Port main has a lower water output than the Stbd at the exhaust but it it difficult to tell. I intend to take the main discharge hose off the raw water pump and run her up to 2k and time my flow into a bucket. I'll do the same to the other and compare. I have another boat that we have used for the past year and am getting the Trojan ready for the summer and just going through several negleted items, so all that has been done is housekeeping and a fuel up (ouch) this weekend.
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Re: raw water pump

Post by mikeandanne » Wed Apr 24, 2013 9:13 am

Here is something that I came across years ago with a carver we had,twin crusaders,one engine always ran hotter ,drove me nuts until I found out that was the engine with the water heater attached and when I plugged that off all was well,can't remember if that engine had a hotter thermostat or not it was a long time ago ,you could pull both thermostats and check then---- as an aside for the last 14 years or so we spent at least a month in PCB beside St. Andrews park, it is like home there.----Mike
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Re: raw water pump

Post by Commissionpoint » Wed Apr 24, 2013 10:01 am

If your pumps and U's, and strainers are all clear and working well your reduced flow may not be a result of having trouble getting water INTO the cooling system, but may be related to difficulties getting it OUT of there. Could be time to pull those manifolds and risers.

Good luck figuring it out.
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sehord
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Re: raw water pump

Post by sehord » Wed Apr 24, 2013 11:04 am

I know.... I am hoping against it. I am starting at the start point and working my way back. I had the intake hose off at idle and let it pump into the bilge... no major water flow but that was only at 750-800 RPM.... I put the hose on with out the hose clamps in place and it didnt really have a back pressure or want to blow off on its own, but that is no test of sorts. It is easier to guantee both the raw water and circulation pumps are moving the correct amount of water first then work back throught the risers and manifolds.... another weekend day project... Ill let anyone know what I find.... on another note... I am not on here much but I do cruise through reading advice all the time. The cost of that is priceless and I thank you all who put in your two cents anytime that you can.... I realize the value of this site so I gladly paid my $15 this morning to help out and encourage anyone who is reading this to do the same.... skip a meal at the fast food joint today and put that money where it'll help!
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Re: raw water pump

Post by gettaway » Wed Apr 24, 2013 12:30 pm

sehord,

Id check the exhaust elbows at the discharge first to see if they have corroded closed or at least restriced by corrosion. It is unclear if you are in fresh or salt water and if you have a raw water or a closed cooling system. I have seen raw water impeller pumps cavitate just enough to impede a good flow, the cause of cavitation in each occurence was worn wear plates in the pump and calcium buildup within the pump cavity. it looks very mnimal, but when the pumps were properly cleaned and rebuilt, the flow returned.

If you are able to get to the raw water intake hose easily, you could try connecting a water hose to the intake and running with the added hose pressue through your cooling system, if you cooling issue is resolved, it might help narrow it down to the pump.

Hopefully you'll find the issue soon and as the TBOY, thanks for supporting the forum!
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sehord
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Re: raw water pump

Post by sehord » Wed Apr 24, 2013 12:42 pm

Yes I am in salt water and have a closed cooling system. I did pull the inboard elbow and it looked good, but that was end of summer last year. I have a 1/4 turn valve opposite my sea strainers for flushing with a hose which I generally do once back in from a trip in the gulf so I can try the hose and see if it drops it... Its an easy chance (and I like easy....) good advice...
I havent pulled the impellers yet, so I am going to open it all up saturday and see what I can come up with, in addition to replacing the temp sending unit at the same time becuase my IR gun shows a lot different temp then both my guages, but they gauges themselves (upper and lower stations) are consistent.
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Re: raw water pump

Post by Commissionpoint » Wed Apr 24, 2013 4:07 pm

Scott makes good points about the elbows too. I am still hanging my hat on a riser or manifold. Hopefully its a piece of seaweed somewhere where it shouldn't be or some such and not a major problem.
1978 F-32 "Eclipse"
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Re: raw water pump

Post by 1995 390 express » Thu Apr 25, 2013 6:06 pm

this may sound crazy but it happened to me last year. i had one engine running 20 to 25 degress hotter with good water coming out the exhaust but not as good as the other side. it turns out that when i had the exhaust sytem removed to put in a new engine i put one of the 4 inch or so hoses on backwards and it has a back flow damper in it. when water was exiting the riser it was closing the damper instead of opening it. good luck

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