Brewing Master

Question:

I’ll add in my $0.02 since I just did something similar   recently. : Thanks for the tips.  I bought a ‘95 Malibu Sunsetter from a guy that would : crank the engine for a few seconds (dry) before launching.  I do that frequently, and have never had a problem.  I hate getting the boat in the water and then finding out it won’t start.  So when I am in line for the ramp, I just crank the engine until it fires, then shut it off.  No "warming it up", just a fire and off.

 I’ll second that this is not a good idea- it’s like running   your car engine between oil changes   I have an older inboard and the impeller is actually separate   from the waterpump itself (Ford 351 PCM).  While replacing   the waterpump recently, I popped off the fan belts and manually   turned the flywheel or whatever it is that spins the impeller   in its own housing unit.  I could hear the rubber inside against   the metal.  It was nice and snug- not tight (swelled impeller?)   and not loose either (broken/worn down blades).  So by   just removing a fan belt on my inboard, I can make a very educated   guess about the current condition of the impeller without   having to tear it apart.   But make no mistake- there *is* friction on that impeller,   and running a boat without water cannot help make that any   easier on the impeller. And then there are the folks who running the engine after pulling it out of the water and revving the engine just to clean out all that bad water…… go figure.

  Again a bad idea- what is "bad water"?  If people are that   paranoid they should carry a bottle of Evian and a funnel   and pour it in directly after each ski session   BTW, when taking apart that old waterpump on my inboard,   a lot of water came out- the engine block holds quite   a bit of water, so winter-proofing a boat so that water doesn’t   freeze and crack a block is very good advice indeed.   I estimate that you would have to run your boat for several   minutes on land if you wanted to purge the "bad water" [sic], and   even then there would still be water in your block.  It   is simply not worth the risk of prematurely wearing out the   engine. —                                                  Doug Fierro                                       |         Atria Software

Response:

: Thanks for the tips.  I bought a ‘95 Malibu Sunsetter from a guy that would : crank the engine for a few seconds (dry) before launching.     I do that frequently, and have never had a problem.  I hate getting the boat in the water and then finding out it won’t start.  So when I am in line for the ramp, I just crank the engine until it fires, then shut it off.  No "warming it up", just a fire and off. : BTW I was able to make a home-brew version of the "fake-a-lake" system for : about $8 in misc. PVC pipe and a toilet plunger.   I have a TEE fitting on the line between the water pump and the through hull for the water intake.  The Tee has a water faucet, and a "reverse coupling" on it.  To run the boat at home, I simply hook a garden hose to the Tee, open the valve, and turn on the hose.   When the engine is NOT running, the water simply runs out the through hull fitting.  When the pump starts turning, it draws what it needs, and the excess continues to flow out the through hull.   This has several advantages to the "fake lake". 1) There is nothing to fall off right when you need it the most.  2) Cheap and simple.  3) It stays with the boat.      Rod McInnis

Response:

: Thanks for the tips.  I bought a ‘95 Malibu Sunsetter from a guy that would : crank the engine for a few seconds (dry) before launching.    I do that frequently, and have never had a problem.  I hate getting the boat in the water and then finding out it won’t start.  So when I am in line for the ramp, I just crank the engine until it fires, then shut it off.  No "warming it up", just a fire and off.

While what Rod is saying may work for him. I have to disagree with the practice. Firing the engine with a rubber water impeller, no matter how long, without water can’t do it any good.  How many revolutions does that pump turn just firing the engine? How many launches per/year? I understand wanting the boat to start once the trailer is in the water, but I’ve never had a time when it didn’t start. Knocking on some wood – oh I guess it’s all fiberglass now And then there are the folks who running the engine after pulling it out of the water and revving the engine just to clean out all that bad water…… go figure. BTW not only look for missing blades on these little guys, but also look for swelling. I pulled one this spring that had swelled to the point it was 1/8 larger in diameter and thickness. This tends to bend the blades even more than normal. The local marine dealers say it was common, but I had never noticed it before, maybe I never looked for it before. John

Response:

Given the hassle to check the impeller (and replace the gaskets) I find it easier to just spend a couple of more bucks and just change the impeller whenever I suspect it ought to be inspected.

Response:

In the northeast we usually open up our pumps once a season during winterization or if it overheats. If you have a good intake strainer and the engine is fine then the impeller can last years. You can check out the impeller of the seawater pump by removing a hose and looking into the pump and rotate and check each blade. If you see chucks missing then time to replace. Removal of the cover and pulling the impeller causes more wear and damage than its worth. Check out THE ENGINE ROOM at http://www.ici.net/cust_pages/cusdn/ using Netscape. Bryon Kass webmaster

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: As far as inspection, I would think that there should be regular interval : inspection, not simply when you see problems. It doesn’t take : more than a few minutes to pop the cover and inspect. I would say every : 100 hours at least, maybe more depending on the quality of the water : you are running in. Terry should count his blessing that his engine is so easy to work on……    I have had several inboards, each one different in respect to engine access.   The Tournament ski boat allows full access to all sides of the engine, once the cover comes off (off, verses just tipped up). Impeller replacement can be done with a screw driver and crescent wrench, and while it would take me more than a "few" minutes, it can certainly be done in less than an hour.  I carry spare impellers (the pump has two) in the boat.  I inspect the impellers occasionally, and have pulled it apart whenever I suspected a cooling problem.   My big, twin engined cruiser is a little different.  You get to the engines by lying on the deck and dangling down the hatch opening.  The water pump is on the bottom, so getting to it is a real pain (headache mostly, as all the blood rushes to your head while you are doing this.)  With twin engines, I will wait until one fails before I go through that hassel.   Now, the cruiser I had before was even worse.  A 25′ Stephens, wooden hull, single engine.  The hatch over the engine was just large enough to access the top, no access underneath.  To get to the water pump/starter/alternator, you had to enter the "bilge" from the rear hatch, crawl forward until you were alongside the engine, play contortionist to work yourself into a spot between the gas tanks, batteries, and exhaust manifolds, and then try to work while you were lying on the stringers and ribs.  Not a pleasent job.  I had the water pump off once because of other work I was doing, and I changed the impellers then.   If you know what the replacement impeller for your boat is, I highly recommend carrying replacements.  Note that many pumps are duals, so yours may need two.  Even if you can’t change the impeller yourself, being able to provide the necessary parts to a mechanic may slavage your vacation.     Rod McInnis

Response:

Dear Bill, I recommend changing the impellor at least bi-yearly if not on a yearly basis.  An impellor is a $25 part an overheated motor is much more expensive.  Your Merc has a plastic water-pump housing which will distort if your impellor runs dry.  Frequently (every other trip)  check your transmission cooler for debries that could "block" cooling water from getting to the waterpump impellor or install an in-line filter between the intake and the trans cooler. This facilitates easy cleaning and even when full of junk will still flow water to lessen the chance of impellor damage.  This in-line is a must in salt water or high-debris applications. I’m a Nautique dealer and our boats come standard with a brass Sherwood water pump and in-line filter.  The brass pump means if you do eat an impellor its unlikely you could damage the pump. I’ve had many customers come in for routine service and their filter looks like a "rats nest" and the impellor is still working to cool the motor because the filter has enough surface area to flow water even when full of junk. The mercruiser system you have works well but will work better with an in-line filter.  If you want to verify your water pump is pushing cooling water try this the next time your out….After the boat is hot and has sat for 5-10 minitues touch the water- pump housing and it should be warm to hot.  Start up the boat and you should be able to feel an almost imediate drop in the temp of the housing as it pulls in cooling water.  WARNING stay away from belts and spining engine parts with loose cloths and your body !  You can use this method anytime to verify cooling! Last…. when you change out your old impellor, if its still useable …put it in a ziplock bag and throw it in the glove box just in case!                                                      TJSSKIER P.S.  If you need a filter call my service manager Bill at 909-          784-5454.  Let him know if your hose is 1 inch or 1 1/4.

Response:

[...] As far as inspection, I would think that there should be regular interval inspection, not simply when you see problems. It doesn’t take more than a few minutes to pop the cover and inspect. I would say every 100 hours at least, maybe more depending on the quality of the water you are running in.

Thanks TJ (and others who’ve emailed me)!  I guess I’ll have a look at that puppy, and I’ll pick up a spare. I am actually of the impression that the "fake a lake" type system is very beneficial to use for that first time start of the season rather than just dropping it in the lake.

I always do this anyway.  That first start of the season is often a difficult one, and I’d rather sit in my driveway waiting for the fuel pump to get gas to the carb than do it at the bottom of the launch ramp while other people are waiting for their turn to use the ramp. Bill Walker, QUALCOMM, Inc., San Diego, CA USA

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The owner’s manual for the Mercruiser 350 Magnum Tournament Ski inboard in my Tige’ (this is a straight inboard, not an I/O, just to make sure snip… snip… tj

Thanks for the tips.  I bought a ‘95 Malibu Sunsetter from a guy that would crank the engine for a few seconds (dry) before launching.  I just replaced the impeller at 120 hours, just to be safe.  Those paper gaskets are sensitive!  Buy a few spare for the assembly process.  Mine leaked after the first assembly attempt, only to find out there was a wrinkle in the paper…. BTW I was able to make a home-brew version of the "fake-a-lake" system for about $8 in misc. PVC pipe and a toilet plunger. -John- — Opinions expressed (or implied) are that of author and nobody elses!

Response:

The owner’s manual for the Mercruiser 350 Magnum Tournament Ski inboard in my Tige’ (this is a straight inboard, not an I/O, just to make sure everybody’s clear on this) says to inspect the raw water pump impeller "whenever a loss of cooling efficiency is noted".  That’s it.  No hours, no months, just "check it if you think there might be a problem".  The motor (and pump) have 140 hours on them, and I never, ever crank it over without water being supplied to the pickup.

Just to pass on the advice that I received regarding the water pump impeller… It was unanamous that you should carry a spare impeller with you. They are rather easy to change "in the field" and you can save yourself a very long paddle or engine damage. Replace the foam gasket on the cover at the same time for $1.30 as well! Make sure you get the impeller baldes bending the right way as you install the new one. Look carefully at the old one before you take it out. The other good advice was to remove the impeller for winter storage. Spray it with Armour-All and put it in a plastic bag for the winter (assuming you have winter!). It helps to have some spray on it again as you install it so that the first few revolutions before the water gets to it are not as brutal. It has to suck water quite a ways, unlike an outboard pump that is immersed in water as soon as it hits the lake. As far as inspection, I would think that there should be regular interval inspection, not simply when you see problems. It doesn’t take more than a few minutes to pop the cover and inspect. I would say every 100 hours at least, maybe more depending on the quality of the water you are running in. I am actually of the impression that the "fake a lake" type system is very beneficial to use for that first time start of the season rather than just dropping it in the lake. These actually force water into the pump, which is a lot easier on the pump than having to run dry sucking up a full hose full of water before it gets lubrication and cooling (the water cools the impeller as well as lubricating the blades wiping on the housing). Also, a hint before you actually see overheating. You might notice the boat is louder than normal. When the pump is working poorly, you aren’t getting as much excess water flowing through the exhaust system and this results in louder exhaust. But don’t worry if you miss this hint… overheating is pretty close behind, especially at idle. Also, as Bill mentions, cranking it over or running it for even a few seconds in the driveway without a "fake a lake" device is almost certain death for the impeller. Even if it doesn’t die on the spot, you can be assured that you have reduced the efficiency because the impeller blades will heat and deform permanently and not work as well. It just isn’t worth it. Hope this helps some other skiers this summer. tj

Response:

The owner’s manual for the Mercruiser 350 Magnum Tournament Ski inboard in my Tige’ (this is a straight inboard, not an I/O, just to make sure everybody’s clear on this) says to inspect the raw water pump impeller "whenever a loss of cooling efficiency is noted".  That’s it.  No hours, no months, just "check it if you think there might be a problem".  The motor (and pump) have 140 hours on them, and I never, ever crank it over without water being supplied to the pickup. With stern drives, the water pump impeller is sort of a "regular inspection" item.  Why should it be different for inboards?  From what I can see in the manual, it uses the same sort of rubber-bladed impeller a stern drive does.  What do people think about this?  Inspect annually, biannually, every 100 hours, or only after it starts overheating?  The latter is what the manual says, which seems a little less than ideal to me. Bill Walker, QUALCOMM, Inc., San Diego, CA USA

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