Yamaha waterpump failure rate

[Jersey Jim]

Johnsw, I just had my 2002 Yamaha F115 water pump and T-stat changed yesterday. I've had the boat only a month but it's the original waterpump. I'm assuming original T-stat too. The motor had 149 hours on it, albeit 6 years old, the impeller was in perfect condition and very pliable. The flat stainless plate was barely scored 0.001", if even that. The plastic housing looked fine too. The thermostat however looked like it was ready to be replaced. The boat was kept in a slip prior to me owning it, so I assume there was always plenty of deep water to avoid debris from being drawn in. I was pleasantly surprised and will always insist on OEM parts. I may never get the opportunity to put aftermarket kits to the test like this, so will never know of their longevity.

Does anyone know if fresh water rinsing has a bearing on the longevity of the impeller rubber?

Jim

 

[DaleH]

Does anyone know if fresh water rinsing has a bearing on the longevity of the impeller rubber?

I highly doubt it one bit. Most nowadays are more of a viton or nitrile synthetic versus old 'rubber' that used to be on the market, that would craze and turn brittle.

Personally I've removed impellers with 8 or more years on them (not my own both small OBs and 1 V6) and though curled a bit, no impeller had any cracking or showed any kind of deterioration from salt exposure. Encrusted salt was found all through-out the water passages including one small OB where I had to remove it with drills and a Dremel too.

As I stated, I believe an impeller will last MUCH longer than even a 3-year replacement interval ... but the cost is too great not to do so at least every 2-3 seasons.

 

[Jersey Jim]

Dale, I was unaware of the synthetic material being used for the impellers. By the time my OB is remotely near needing replacement, my limited, and the forum's extensive first-hand knowledge (such as yours) will aid me in making a better decision as to the replacement interval. From what I've seen so far the t-stat will prompt the replacement before the W/P will need it. But once you've gotten that far in there, it would appear foolish to not change out the pump as well.

Thanks.

 

[BuddahB]

Just did waterpump on my 2003 for the second time. Motor has just under 600 hours. Replaced T-stats now for the first time. A bit tricky but can be done yourself. Starboard stat and passage looked good. Port T-stat looked same but quite a bit of sand in that passage. Glad I changed them this time around. From now on I'll do them every three years when I do the waterpump service. Waterpump looked like new and could have gone much longer, but I do quite a bit of boating in the shallow sandy bottom Barnegat Bay in NJ

 

[johnsw]

Been off line for a while, and finally catching up. Start getting ready in a couple weeks to launch soon. Thanks to all for the comments. Figure I'll be good with the pump for at least a few more seasons. It's an '04 motor with less than 200 hours. Guessing it was not in bad shape when rebuilt in the fall, and sounds like they're not too fragile and can hold up reasonably well.

Sand can definitely be an issure. I'm not far from you BuddahB, so we at least spend some time in the same waters and maybe on the same shallows. Not sure if I'll get to the thermostats before launching, but something for my 'to-do' list maybe on one of those days when I'm puttering at the dock.

John S.

 

[Chop~Chop]

Are there standard procedures one uses for RPM control when providing adequate water flow through the muffs.

Since a little higher rpm creates considerably more flow than @6-700rpm idle. Seems like upwards of 2000 rpm for a short while wouldn't be a problem?


I'm only familiar with the older Merc Type I drives whose impeller is actually fitted with a brass ring insert and we'd cringe at the thought of running even at 1500 rpm. Maybe though, we've been too cautious all along.

Last fall I solved the "adequate flow" problem by ditching the $30 dual input flow rectangular muff. I substituted it with the $4 singular input circular muffs which fit very very tightly around the irregular shaped lower unit. The tell-tale pee'd as if it were dunked

Thanks, Mark

 

[johnsw]

Not sure about RPM issues using muffs, but I generally keep it at idle or slightly higher (1K max) until the fogging oil burns off. Never had a need for much else.

I started the engine last week for the first time after winterizing, and overheated after about 10 minutes on the muffs. Pee stream was OK, but checked the hose and connections for restrictions. I'd think it unusual to overheat on the muffs if water pressure is OK, since using them creates a pressurized cooling system rather than having the pump pull water from the supply. So I bought a pair of thermostats and gaskets from the local dealer and set about to install them. I noticed the starboard cylinder head noticably hotter to touch than the port side, so that's where I started. When I removed the thermostat housing, I found that one of the two housing passages that feeds water from the cylinder head water jacket to the cylinder head cover water jacket was about 3/4 blocked up with sand. It's a small passage to begin with, maybe 1/8" deep by 3/16" wide. Cleaned out all sand I could find in the housing, replaced both thermostats and gaskets since the housings were coming off anyway, and retested running the engine at idle for 30 minutes without an alarm.

I've now got a Teleflex OB water temp kit I'm going to install next time I'm working on the boat. Only thing I need to find is a suitable switch I can mount on the console. Since each cylinder head has it's own overheat thermoswitch, I'm going to put senders on each side and plan on using a switch to connect the guage to each side independently. Problem is the console face is thicker than most mounting shafts of the switches I can find, so I'm not yet sure how I'm going to do the hook up. Anyone done something like this, or similar? The other option is a gauge for each side, but I'd rather not go that route for a project like this.

John

 

[DaleH]

Are there standard procedures one uses for RPM control when providing adequate water flow through the muffs.

Since a little higher rpm creates considerably more flow than @6-700rpm idle. Seems like upwards of 2000 rpm for a short while wouldn't be a problem?

I myself would NEVER put an OB about high idle (1200+ or so) on muffs. I've seen many a V6 motor overheat using single feed muffs too ...

 

[johnsw]

Agreed. First thing I thought of was not enough water through the muffs. But since I do this every season without issue, I was doubtful but I know it can happen. The unscientific, inaccurate touch test made me think it was something else. When the alarm sounded, I shut down and checked my water supply. Finding essentially nothing, I then felt the cylinder heads (an actual gauge would have been better). I could easily hold onto the port side, but starboard was bearly touchable. Pulling off the thermostat housings and finding sand where I did gave me a sense of a simple fix. After cleaning and new thermostats on both sides, 30 minutes on the muffs at idle without an alarm makes me think that was my problem. Not much else I can do at this point until I can launch and test everything under load with the water pump working as it's supposed to. Hopefully, I'll get the temp gauge in before then.