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Which pump is correct

C

concritter

Regular Contributor
"Here are the details...454-33

"Here are the details...454-330H.P...2 weeks ago an impellar broke.No problem-at anchor I put my spare pump on I purchased new last winter.Both engines always ran 170-175 degress,nothing wrong at all with that.New 160 thermostats put on in spring.The original water pumps are Sherwood-35, but the one I bought is its newer replacement, which is a Jabsco pump.They look alike, but now for 2 weekends that engine is running around 150-155 degrees.Not as much steam behind me as I always seem to have.Are the Sherwoods worn that much or is the Jabsco that much better?Also...which actually is the better temp to run?....Todd"
 
"I am going to give you my tho

"I am going to give you my thoughts about raw water pumps. Be careful to know that I am an experienced boater but that experience is limited to 20 years with my 50' Gibson (2X454 CID) and a few sail boats.

I am convinced that the steaming problem at the exhaust is the result of less than designed water flow. I believe it is exacerbated by a number of things like high humidity and low temperature. I also believe that short of installing a flow meter in the water line it is not possible to know the flow without measuring it with a bucket. Crusader informed me that the flow should be 12 gallons per minute at 1000 RPM. Back in 2002, I measured my port engine at half that amount. I replaced the pump and measured 12 gallons per minute. Overtemperature problems resolved and no steam from that engine.

The problem with my pump turned out to be wearing away of the front and back plates caused by sand in the mighty Mississippi river.

Regarding the temperature after changing out a pump, unless the flow has been really low, I would have expected the thermostat to regulate the temperature. Are both engines running the same temperature?

Chuck Hanson"
 
"Thanks Chuck for your reply.B

"Thanks Chuck for your reply.Both engines always ran at 170-175 for the past 2 years that I have owned this boat.Right after I installed the new pump I am showing 150-155 keeping in mind the 160 thermostat which controls the temp.At first I thought it may be a sensor that quit on me, but shooting it with my temp gun has showed me that yes I am at these lower temps.Ran last weekend for 3 hours and stayed at 155 while the other was at 175 and both have new thermostats this year.Noticably less steam as well.My real question is....Is 150-155 to low?Is it better for the engines to have more heat than that?I am probably the only guy on this site wondering about a too cool condition.The replaced pump is again ready to go as a spare, but if 150 is OK than I am going to buy another pump for the other side as well....Todd"
 
"My guess would be that on the

"My guess would be that on the hotter engine your thermostat is open all the way and you don't have enough water to cool to 160 degrees. I would change the pump, especially since you already have a new spare.

When I bought my boat 20 years ago it did not have thermostats in either engine. My mechanic friend told me the engines are designed to operate at a specific temperature. In the case of my engine it is 160 degrees F. The temperature specification is part of the lubrication scheme. I don't think the solution to low temp is cutting back on the raw water, it is in the thermostat.

I will have to defer to someone like Jeff as to whether 150 degrees is too low.

Chuck Hanson"
 
Hi Chuck...
This makes very l

Hi Chuck...
This makes very logical sense to me... My starboard engine has a water pump 1 yr older than the port yet both cooling systems we totally replaced this spring. My older pump has a touch of steam when the newer one does not
 
"Hey guys, very interesting th

"Hey guys, very interesting thread. I want to replace my water pumps as my temps are running 175-180. What pumps did you purchase and where? Is jabsco better than the sherwood?"
 
"Since both pumps--properly op

"Since both pumps--properly operating--produce excess water flow, then the motors should run the same. If not, something else is the problem.

Jeff"
 
"Well guys...I do not know wha

"Well guys...I do not know what else to say except,took an older pump off that was running at a fine 170-175 and switched to a Jabsco 42730-0000 and right away we have 150-150.Have about 4 hours on it and still one at each of the above temp ranges.Believe I will get another pump, but still have doubts on if this is too cool for engines running 3300-3500 rpm's.But then again they want 160 T-stats which you would think would put you around 155....Todd"
 
"If I have read your last mess

"If I have read your last message correctly, you have solved the problem of temperature. Are you still steaming at the exhause or has that also been eliminated? Regarding the 155 degrees, I would not worry about it. I would imagine this is within the accuracy of the temperature instrument.

Chuck Hanson"
 
"Well Chuck I just got home fr

"Well Chuck I just got home from another weekend of boating and all is still running well and as stated above.The steam is remarkably much less.I have not been able to find out the GPM of the Sherwood-25 pump, but the Jabsco flyer I looked at this weekend states 60GPM.As for accuracy equipment...both the gauge and temp gun confirm the same.Jeff I feel is correct that both pumps put out enough water, and there actually is no problem at hand.More of a question of is one perhaps a bit better than the other one.Guess I will have to put a Jabsco on the other engine and see what gives.....Todd"
 
"This STEAM thing has my utmos

"This STEAM thing has my utmost attention as 90% of the boats in Barnegat Bay that I see do NOT show steam. While a few factors may contribute to this such as newer engines or fuel type..MINE (FWC) steam. Some days it is rather intense like 15 feet behind the boat. I had mounted a 120 qt cooler on the swim platform but IF I fill it with some ice, the surrounding warm steam will melt it and actually warm the melted water somewhat....

I have all new manifolds, risers, new water adapters between the manifolds and elbows, new e-35 Sherwood pumps, u-coolers are 1 new and 1 just cleaned, dual 4" exhausts on both engines stepped down to 3" about 18" after the elbow. I like the concept of not having enough water flow spraying on a hot surface creating steam. Makes sense

With what I am reading above about raw water pump flow volume, does anyone really think this could be it? Is there a difference on their spec sheets? With all I have been thru in repairng these engines, I have no objection to changing 2 raw water pumps if that has a chance at eliminating the steam."
 
"Todd:

I switched to those

"Todd:

I switched to those jabsco pumps after 4 years of dealing with the sherwood e-35's and haven't regretted it one bit. Working on the Jabsco's is easier and cheaper, too. The Cams seem to last longer and the bearings are the same as those used on the Delco 10-SI alternator.

Neither one likes silt or sand - what pump does - but the jabsco seems to tolerate it better. Take one of each to a mechanical engineer and get their opinion regarding the designs.

The impellers are interchangable if you have spares. I believe the cams cam be swapped, too, but it requires a minor mod, if I remember right. (Think Jabsco needs a roll pin to locate the wear plate)."
 
The answer is the Jabsco 42730

The answer is the Jabsco 42730-0000 pump Al.To my way of thinking...Crusader wants us to have 160 thermostats for a reason or they would have picked another range.Thermostats control your engine temp.Usually your engine will reach that temp and then drop back a bit and there you are.That would be 155 or so as I see it.Which brings me to the point of buying another pump.This is a biggy as a lot of money rides on these pumps.....Todd
 
"Hi Todd,

Actually, my rock

"Hi Todd,

Actually, my rock steady starboard engine is ALWAYS 160. It's the steam I am STILL totally confused on. Why do these engines blow steam and more at times than other times...IS IT REALLY normal?

IF it is cooling and cooling to the set levels, what is the steam from? As I would understand it, water is hitting a hot thing and then turning to steam.."
 
"I believe the water coming fr

"I believe the water coming from the exaust pipe should be less than the thermostat setting. The reason for this is that the water pump delivers more water than is needed to cool the engine. The excess water is dumped to the exhaust manifold further cooling the water on the way to the exhaust. Cool it enough and you will not have "steam" coming from the exhaust pipe.

The other thing that could be going on with some engines may be inadequate mixing of water and exhaust at the exhaust manifold. If improper mixing takes place, some exhaust gas may pass without being cooled. This gas would have sufficient temperature to be seen as steam.

Maybe someone who knows the internals of the mixing zone in the exhaust chamber could clarify this.

Chuck Hanson"
 
"Thanks Chuck... The Steam I g

"Thanks Chuck... The Steam I get is about 15 feet behind the boat when running about 3000. While in NO WAKE zones, It's barely noticable. No engine overheating according to the instruments, JUST STEAM....

I almost start to think that THIS must be where the phrase " Full steam ahead" comes from ! Surely different than " Cold enough to freeze the balls off a brass monkey ""
 
"Alright guys, I have been rea

"Alright guys, I have been reading this and I am a newbie. I have two questions. 1. Is it hard and expensive to just go ahead and replace the pump. If it is cheap and easy (doubtful) You guys have me thinking of changing out mine.
2. Why is no one asking these questions to Crusader? Do they not read this board, or do they just not have a number to call and get these types of questions answered.

Once again, thank you gentlemen for your time and effort in helping the people like me in this group. Special thanks to Mako, Jeff, and Chuck.


Shannon"
 
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