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Author Topic:   Outboard Engine Water Pump Service Interval

Landlocked posted 01-22-2014 01:32 PM ET (US)
The 15-degree weather we experienced this morning has me thinking about warmer days and what I need to do to prepare for our 10 day Florida trip at the end of May. The 2002 Mercury 90-HP two-stroke-power-cycle outboard I bought new for my Montauk still has the original water pump. It's still pumping strong and I've had no overheating. Since new, the boat has probably made five week-long trips to Florida and gotten an additional five days average use per year, so, assuming six hours average running time per day of use, I'd estimate maybe 550 hours on the motor--which is probably way more than actual. Wish I'd installed that hour meter that is still rolling around in the bottom of my box of boat stuff.
I'm looking for opinions as to whether or not I should replace the pump for safety's sake before this year's trip, and, if so, some idea of cost to have it done. I've replaced pumps on several 15 to 25-HP outboard engines before and not had problems other than with aligning the shaft, but, for some reason, I just don't feel up to tackling this. Guess I'm getting old, lazy or maybe my wife is right and it's both.
Only maintenance this motor has ever had is a change of plugs two years ago, and it runs like a top. Knowing that, would there be any other maintenance you would suggest if I'm going to take it in, anyway?
Most of my time in Florida is spent in the bays with maybe one or two trips out no more than five miles.
Thanks for your opinions,
Ll.

Landlocked posted 01-22-2014 01:34 PM ET (US)
Add lower unit oil change annually. I forgot about that one, but I've not missed a year.
Ll.
retired posted 01-22-2014 02:03 PM ET (US)
I replace the water pump every two to three years. The cost involved is minimal and there is one thing less likely to ruin your ruin your 10 day trip. You can easily do this yourself.
kwik_wurk posted 01-22-2014 05:27 PM ET (US)
If you are a DIY type, I would replace every 2-3 years. I like getting in just to crack the bolts so nothing freezes up. I have not paid for an impeller replacement on an outboard in 10-15 years, so I have no idea the cost anymore.
The material of the impeller does age (gets rigid and cracks), so lifespan is an issue.
If you are taking a weeklong vacation, it would be a shame to have it punctuated with a bad pump.
Landlocked posted 01-22-2014 05:45 PM ET (US)
I'm a bit more DIY when it comes to carpentry than mechanics but I'm capable. My boss at my first company was animate that I replace the impellors on our small work boats every year.
They were smaller motors though and the lower units were light and a little easier to work with trying to get things lined back up to reassemble than I suspect this one will be. There is the issue of the thing never having been opened up as well. I imagine the bolts will be tough to get out and need a little spray lube to break loose. Seems like the steering linkage freezes up every year no matter how much I flush and lube it before putting it up for the winter.
Thanks for the responses. Sounds like the consensus is what my gut was telling me. I'll replace it.
Ll.
Tom Hemphill posted 01-22-2014 06:35 PM ET (US)
I think it is prudent to drop the lower unit at least every three years of salt water use, whether it needs it or not. This is based on my experiences with a frozen driveshaft, identical to what is described in this old thread:
http://continuouswave.com/ubb/Forum3/HTML/009982.html
fno posted 01-22-2014 09:55 PM ET (US)
I wrench for a living and drop the lower on my Yamaha-made Mercury-branded 225-HP engine every two or three years to break the bolts, replace the impeller, and, of course, check and usually change the oil. It is not that hard to do, even on a larger motor. I am somewhat old (52) and extremely lazy. Get to it so that trip to Florida is worry free.
jimh posted 01-23-2014 11:05 AM ET (US)
To evaluate the condition of the water pump, it would be better to have a water pressure gauge and to have been noting the reading of water pressure as a function of engine speed for the past decade. If that data were available you could make a better assessment of the present condition of the water pump. Even without the data, we seem to be talking about a water pump that has not been serviced in 12 years. That is a very long time to go between service intervals for an outboard engine water pump, and particularly for a Mercury outboard, whose water pumps are usually specified to be changed annually by the service manual or operating guide.
I can understand the reticence to perform the service yourself. The last water pump I changed myself was on a 50-HP engine. The gear case on a 90-HP engine is often the larger size gear case, much like you'd find on a 150-HP or higher engine, and there is more weight. It is also usually a chore to re-install the gear case single-handedly, as it often takes more than two hands to get all the components aligned and to bear the weight of the gear case.
Your cost to have the service done will vary with your location, but I would estimate about $125, and perhaps more if more parts are replaced than just the rubber impeller. Some water pumps need seals and wear plates. I'd figure the dealer will charge you the cost of the parts at full retail and at least one hour of labor.
6992WHALER posted 01-23-2014 03:11 PM ET (US)
On my 1991 200 Yamahas I have always replaced the water pumps every two years.
I should have changed the water pumps for the start of the 2013 season.
With 22 days of rain in April and snow in May I just did not get it done before the boating season. I was not too concerned as both engines were pumping water fine.
The last week of August up on Isle Royal National Park the port engine started to run hot at idle. It was fine as long as I maintained a little bit higher RPM, so I did not have to change the pump during the trip. But I will be changing them out this Spring. I will be going back to my every two years from now on.
Landlocked posted 01-24-2014 10:19 AM ET (US)
Thanks all,
I guess I had convinced myself it was fine because the boat gets so little use. After adding up the trips and estimating hours though it appears it has had a lot more than I thought. Didn't get a vacation last year so I sure don't want to mess up this one. I'll change it.
Rented a house with two docks - one on the bayou one and one the bay. Will be thinking of little else for the next few months.
Ll.
wbullwin posted 01-29-2014 08:05 PM ET (US)
I just sold my 2003 170 Montauk with a 90 Hp 2 stroke last Spring. Over the Winter of 2012/13 I replaced the impeller myself for about $40 for the kit. There is an excellent youtube video about 10 minutes long explaining exactly what to do, when. Or you could have a Merc dealer do it for around $200. Either way, you are walking on thin ice with an impeller that old. It's not only the use, it is the age that kills the rubber.
CHANGE IT!!!!!
wezie posted 01-30-2014 08:54 AM ET (US)
It seems that OEM rubber parts are better or more consistent than after market.
That will be my decision soon when I replace my low hour, 8 year old water pump.
bloller posted 01-30-2014 10:28 AM ET (US)
If it is such an important maintenance item then why have designers buried them inside the lower unit? Just wondering
picflight posted 01-30-2014 11:39 AM ET (US)
"why have designers buried them inside "
I think that is because there is no other simpler way of moving coolant fluid.
I too changed the impeller, base and cover, the whole thing, with a Sierra kit. Cost was about $40 for the kit. I found sand inside the housing, glad I cleaned it and flushed the entire cooling system. While I was at it, I changed the Poppet valve and thermostats as well. These two items as well as the impeller were in good condition, no damage but because I found sand in the impeller housing, I decided to clean and replace all the cooling system components. I just feel better now that it is all new.
I suggest you do the same. The cooling system is the backbone of the engine.
mtwilling posted 01-31-2014 10:51 PM ET (US)
I had mine changed on a 135 Mercury a few months ago. My engine had overheated because of clogged tube but while trouble shooting the [malfunction] I asked my mechanic to change the three-year-old impeller. The cost was very reasonable at about $135 and was performed by a Mercury dealer.
sosmerc posted 02-04-2014 11:47 PM ET (US)
The 2002 Mercury 90-HP has a [water pump with a] very durable and dependable design. I don't see many problems with this model, and I am often tempted to disregard annual water pump service on these engines. BUT, every now and then I DO see the hub starting to show signs of separation, and when this happens you are in trouble. Why take a chance? If you drop the lower unit and at least inspect the impeller every season, it will become a relatively easy routine, and you won't have to worry about stuck driveshafts and seized bolts when the time comes that you really do need to replace the impeller.
Landlocked posted 02-05-2014 11:50 AM ET (US)
Made arrangements with a buddy this weekend to use his garage and replace pumps on my boat and his on the same day. Appreciate all the advice.
Landlocked posted 04-14-2014 02:05 PM ET (US)
Just wanted to say that I finally got around to replacing the pump this past weekend. Even though the lower unit had never been removed from the boat, all it took was a few light taps with a rubber mallet and off it came.
Replacing the pump and gaskets was easy and straight forward. Only advice I have is ignore that U-TUBE video about putting the boat in forward. Put it in Neutral. Entire job took about 30 minutes. Started it up on a pair of muffs after I was finished and the water stream from the motor was at least twice as strong as it had been before I replaced it.
Ll.

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Author	Topic: Outboard Engine Water Pump Service Interval
Landlocked	posted 01-22-2014 01:32 PM ET (US) The 15-degree weather we experienced this morning has me thinking about warmer days and what I need to do to prepare for our 10 day Florida trip at the end of May. The 2002 Mercury 90-HP two-stroke-power-cycle outboard I bought new for my Montauk still has the original water pump. It's still pumping strong and I've had no overheating. Since new, the boat has probably made five week-long trips to Florida and gotten an additional five days average use per year, so, assuming six hours average running time per day of use, I'd estimate maybe 550 hours on the motor--which is probably way more than actual. Wish I'd installed that hour meter that is still rolling around in the bottom of my box of boat stuff. I'm looking for opinions as to whether or not I should replace the pump for safety's sake before this year's trip, and, if so, some idea of cost to have it done. I've replaced pumps on several 15 to 25-HP outboard engines before and not had problems other than with aligning the shaft, but, for some reason, I just don't feel up to tackling this. Guess I'm getting old, lazy or maybe my wife is right and it's both. Only maintenance this motor has ever had is a change of plugs two years ago, and it runs like a top. Knowing that, would there be any other maintenance you would suggest if I'm going to take it in, anyway? Most of my time in Florida is spent in the bays with maybe one or two trips out no more than five miles. Thanks for your opinions, Ll.
Landlocked	posted 01-22-2014 01:34 PM ET (US) Add lower unit oil change annually. I forgot about that one, but I've not missed a year. Ll.
retired	posted 01-22-2014 02:03 PM ET (US) I replace the water pump every two to three years. The cost involved is minimal and there is one thing less likely to ruin your ruin your 10 day trip. You can easily do this yourself.
kwik_wurk	posted 01-22-2014 05:27 PM ET (US) If you are a DIY type, I would replace every 2-3 years. I like getting in just to crack the bolts so nothing freezes up. I have not paid for an impeller replacement on an outboard in 10-15 years, so I have no idea the cost anymore. The material of the impeller does age (gets rigid and cracks), so lifespan is an issue. If you are taking a weeklong vacation, it would be a shame to have it punctuated with a bad pump.
Landlocked	posted 01-22-2014 05:45 PM ET (US) I'm a bit more DIY when it comes to carpentry than mechanics but I'm capable. My boss at my first company was animate that I replace the impellors on our small work boats every year. They were smaller motors though and the lower units were light and a little easier to work with trying to get things lined back up to reassemble than I suspect this one will be. There is the issue of the thing never having been opened up as well. I imagine the bolts will be tough to get out and need a little spray lube to break loose. Seems like the steering linkage freezes up every year no matter how much I flush and lube it before putting it up for the winter. Thanks for the responses. Sounds like the consensus is what my gut was telling me. I'll replace it. Ll.
Tom Hemphill	posted 01-22-2014 06:35 PM ET (US) I think it is prudent to drop the lower unit at least every three years of salt water use, whether it needs it or not. This is based on my experiences with a frozen driveshaft, identical to what is described in this old thread: http://continuouswave.com/ubb/Forum3/HTML/009982.html
fno	posted 01-22-2014 09:55 PM ET (US) I wrench for a living and drop the lower on my Yamaha-made Mercury-branded 225-HP engine every two or three years to break the bolts, replace the impeller, and, of course, check and usually change the oil. It is not that hard to do, even on a larger motor. I am somewhat old (52) and extremely lazy. Get to it so that trip to Florida is worry free.
jimh	posted 01-23-2014 11:05 AM ET (US) To evaluate the condition of the water pump, it would be better to have a water pressure gauge and to have been noting the reading of water pressure as a function of engine speed for the past decade. If that data were available you could make a better assessment of the present condition of the water pump. Even without the data, we seem to be talking about a water pump that has not been serviced in 12 years. That is a very long time to go between service intervals for an outboard engine water pump, and particularly for a Mercury outboard, whose water pumps are usually specified to be changed annually by the service manual or operating guide. I can understand the reticence to perform the service yourself. The last water pump I changed myself was on a 50-HP engine. The gear case on a 90-HP engine is often the larger size gear case, much like you'd find on a 150-HP or higher engine, and there is more weight. It is also usually a chore to re-install the gear case single-handedly, as it often takes more than two hands to get all the components aligned and to bear the weight of the gear case. Your cost to have the service done will vary with your location, but I would estimate about $125, and perhaps more if more parts are replaced than just the rubber impeller. Some water pumps need seals and wear plates. I'd figure the dealer will charge you the cost of the parts at full retail and at least one hour of labor.
6992WHALER	posted 01-23-2014 03:11 PM ET (US) On my 1991 200 Yamahas I have always replaced the water pumps every two years. I should have changed the water pumps for the start of the 2013 season. With 22 days of rain in April and snow in May I just did not get it done before the boating season. I was not too concerned as both engines were pumping water fine. The last week of August up on Isle Royal National Park the port engine started to run hot at idle. It was fine as long as I maintained a little bit higher RPM, so I did not have to change the pump during the trip. But I will be changing them out this Spring. I will be going back to my every two years from now on.
Landlocked	posted 01-24-2014 10:19 AM ET (US) Thanks all, I guess I had convinced myself it was fine because the boat gets so little use. After adding up the trips and estimating hours though it appears it has had a lot more than I thought. Didn't get a vacation last year so I sure don't want to mess up this one. I'll change it. Rented a house with two docks - one on the bayou one and one the bay. Will be thinking of little else for the next few months. Ll.
wbullwin	posted 01-29-2014 08:05 PM ET (US) I just sold my 2003 170 Montauk with a 90 Hp 2 stroke last Spring. Over the Winter of 2012/13 I replaced the impeller myself for about $40 for the kit. There is an excellent youtube video about 10 minutes long explaining exactly what to do, when. Or you could have a Merc dealer do it for around $200. Either way, you are walking on thin ice with an impeller that old. It's not only the use, it is the age that kills the rubber. CHANGE IT!!!!!
wezie	posted 01-30-2014 08:54 AM ET (US) It seems that OEM rubber parts are better or more consistent than after market. That will be my decision soon when I replace my low hour, 8 year old water pump.
bloller	posted 01-30-2014 10:28 AM ET (US) If it is such an important maintenance item then why have designers buried them inside the lower unit? Just wondering
picflight	posted 01-30-2014 11:39 AM ET (US) "why have designers buried them inside " I think that is because there is no other simpler way of moving coolant fluid. I too changed the impeller, base and cover, the whole thing, with a Sierra kit. Cost was about $40 for the kit. I found sand inside the housing, glad I cleaned it and flushed the entire cooling system. While I was at it, I changed the Poppet valve and thermostats as well. These two items as well as the impeller were in good condition, no damage but because I found sand in the impeller housing, I decided to clean and replace all the cooling system components. I just feel better now that it is all new. I suggest you do the same. The cooling system is the backbone of the engine.
mtwilling	posted 01-31-2014 10:51 PM ET (US) I had mine changed on a 135 Mercury a few months ago. My engine had overheated because of clogged tube but while trouble shooting the [malfunction] I asked my mechanic to change the three-year-old impeller. The cost was very reasonable at about $135 and was performed by a Mercury dealer.
sosmerc	posted 02-04-2014 11:47 PM ET (US) The 2002 Mercury 90-HP has a [water pump with a] very durable and dependable design. I don't see many problems with this model, and I am often tempted to disregard annual water pump service on these engines. BUT, every now and then I DO see the hub starting to show signs of separation, and when this happens you are in trouble. Why take a chance? If you drop the lower unit and at least inspect the impeller every season, it will become a relatively easy routine, and you won't have to worry about stuck driveshafts and seized bolts when the time comes that you really do need to replace the impeller.
Landlocked	posted 02-05-2014 11:50 AM ET (US) Made arrangements with a buddy this weekend to use his garage and replace pumps on my boat and his on the same day. Appreciate all the advice.
Landlocked	posted 04-14-2014 02:05 PM ET (US) Just wanted to say that I finally got around to replacing the pump this past weekend. Even though the lower unit had never been removed from the boat, all it took was a few light taps with a rubber mallet and off it came. Replacing the pump and gaskets was easy and straight forward. Only advice I have is ignore that U-TUBE video about putting the boat in forward. Put it in Neutral. Entire job took about 30 minutes. Started it up on a pair of muffs after I was finished and the water stream from the motor was at least twice as strong as it had been before I replaced it. Ll.