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Author Topic:   2001 Optimax 135-HP Water Pump Replacement Procedure
lurkynot posted 03-19-2012 07:29 PM ET (US)   Profile for lurkynot   Send Email to lurkynot  
[The authour says that he is] going to finally remove and replace [the] impellor and water pump kit on my 2001 Mercury 135-HP OptiMax [and that he has] not done it in a few years, so I am sure it will need it. Because I [replace the water pump and impeller] so infrequently I cannot remember if the gear shift needs to be in gear or left in neutral prior to dropping the lower end. Anyone have any suggestions or tips? Thanks.
martyn1075 posted 03-19-2012 10:35 PM ET (US)     Profile for martyn1075  Send Email to martyn1075     
I'm going to replace mine in the next couple of weeks. My engines are a little different model (Optimax 225's) which I am not sure is any different or not in regards to the water pump replacement. However, this article may be useful for your engine.

lurkynot posted 03-20-2012 06:26 AM ET (US)     Profile for lurkynot  Send Email to lurkynot     
Thanks martyn1075.

I found my repair manual DVD for the motor and it has a pretty good illustration of the part breakout. I just seem to remember either having it in gear when reinstalling so that upper splines mesh and foot of the lower mates to the upper casting so the fastening bolts/nuts can be reinstalled.

Also I found a video of a guy doing a Mercury 90 Saltwater on Youtube and he mentioned not leaving any grease at the top of the gear shaft - just on the splines in order to prevent hydraulic lock. First I have ever heard of that though.

martyn1075 posted 03-20-2012 12:27 PM ET (US)     Profile for martyn1075  Send Email to martyn1075     
Most important thing is to put the motor in forward gear before removing the lower end.


lurkynot posted 03-20-2012 07:57 PM ET (US)     Profile for lurkynot  Send Email to lurkynot     
I went over to a dealer I have dealt with in the past "buying parts " only never had service done there and the - what appeared to be the owner or perhaps the manager who seemed very well schooled in the Optimax motor.

I asked about bringing the lower unit in and having him pressure test the lower unit as a precaution since I was already dropping the lower unit to change the pump kit. He asked why as in did you detect a leak in anyway such as water in the gear lube at the end of last season when draining it or something along those lines. I replied no however I was contemplating rack storing the boat and in addition to the pump kit maintenance I was curious about a simple pressure test to ensure the season could potentially be that much more trouble free.

He replied strikingly "what year is the motor" 2001 I replied him "well it needs all new seals in the lower unit you were lucky to have lasted this long". I asked how much to do the job and he replied $350 - $400 then I asked what seals and how many he planned on replacing since he professed the entire lower end needed to be "pulled apart" and of course serviced.

Does this seem right about needing to replace seals that because the motor is 10 years old they "need" to be replaced.

I have had other outboards purchased brand new with boats that I kept for 15 years and never had to have the lower end unit pulled apart and seals replaced as maintenance.

Any thoughts or suggestions?

ALAN G posted 03-20-2012 09:51 PM ET (US)     Profile for ALAN G  Send Email to ALAN G     
Lurkynot: regarding your question about seal life: This could generate a lot of discussion because all us Whaler/outboard owners have had lots of experience and opinions.

So first the opinions: You were on the right track with a pressure test. That can not only determine there is a problem, but can pinpoint the leak location (if there is a leak). The other test is the condition of the lower unit oil when you change it. If clean, don't worry. If milky or water does come out, the seals need replacement.

My experience: After boating for over 50 years and owning over 20 outboards and a couple inboard/outboards, my engines generally had no issues with the seals for 15 to 20 years...but I did all required maintenance and flushed the engines with fresh water after use in salt water. I usually kept them for 10 to 25 years, but I still have a couple that are 27 and 38 years old. I had to replace seals on the "younger" one at 21 years, and the "older" still has the original seals. I recently rebuilt a 1958 Johnson 35 and 1967 Johnson 60. Both needed complete sets of seals.

So, there is no magic time that seals need to be replaced, some go sooner, some go your auto's radiator hoses. Replacing early costs money, but prevents problems. In my opinion, I would check for water/fluid condition every couple weeks during the season, pressure test at the end of the season, and replace the seals when the conditions warrant. Do the oil change maintenance and a visual inspection.

It will be interesting to see what others say!


lurkynot posted 03-20-2012 09:59 PM ET (US)     Profile for lurkynot  Send Email to lurkynot     
Thanks Al I was thinking the same thing after pondering this trip to the parts/dealer today. I will monitor the lower unit as I usually do throughout the season and if I suspect something from a visual inspection I will have the lower unit pressure tested and serviced accordingly.

jimh posted 03-21-2012 08:07 AM ET (US)     Profile for jimh  Send Email to jimh     
I owned a pair of 1987 Yamaha 70-HP engines that I acquired in c.2001. In c.2003 I noticed that the gear case lubricant was showing signs of water intrusion, so I had the rear propeller shaft seal changed. The engines were 16-year-old at that point. The seal replacement was going to cost about $150 (each engine), but there was a complication on one engine. The retaining nut could not be removed and had to be cut and hammered out of position. That added $100 to the replacement cost. The service was just on the rear propeller shaft seal. It did not require the gear case to be disassembled.

There is another seal on the gear case at the drive shaft, where the drives shaft enters the gear case near the water pump. I do not recall having to have any work done on that seal. I think you can also replace that seal without a complete tear down of the gear case.

You should clarify if your mechanic intends to replace both the drive shaft seal and the propeller shaft seal, or just the propeller shaft seal. If only the propeller shaft seal, an estimate of $400 seems high. Maybe he is counting on having a problem with the retainer being corroded in place.

lurkynot posted 03-21-2012 05:50 PM ET (US)     Profile for lurkynot  Send Email to lurkynot     
I have all the bolts undone I just cannot remember how to dis - engage the shift shaft.

The very front portion of the housing are still joined and I do not want to force it.

Does anyone have the procedure.

lurkynot posted 03-21-2012 07:26 PM ET (US)     Profile for lurkynot  Send Email to lurkynot     
Finally got it. Was a bit froze in the front and I threaded up a fastener in the very rear of the housing to counter balance the friction and weight and presto it came loose and all is well.
martyn1075 posted 03-21-2012 09:24 PM ET (US)     Profile for martyn1075  Send Email to martyn1075 my first post there was a link if you click on the link there is valuable information at the bottom. I will attach it here. Its a step by step with diagrams to help.

Good luck! I will next this weekend as its going to be actually sunny here and I have some time. Let me know how it all works out for you.


Martyn Number/191911/page/0/view/collapsed/sb/5/o/93/fpart/1

lurkynot posted 03-22-2012 06:17 PM ET (US)     Profile for lurkynot  Send Email to lurkynot     
Hey thanks martin. In my previous post was where all went good.

I have lower unit on the bench so to speak and the boat is going to the gelcoat guy in the mean time. Should be there a week and this weekend I will swap the pump kit out.

The standard kit came with an impeller which had a fiber or non - metallic core rather than the brass one Sal has been recommending.

Of course the brass one was about a additional 25% of the original kits cost.

The base plate did not look to bad nor did the insert cup. Next time perhaps next spring if the plate and cup look ok I think I will just replace the "heavy duty" impeller.

martyn1075 posted 03-23-2012 11:19 AM ET (US)     Profile for martyn1075  Send Email to martyn1075     
I went for the quicksilver basic kit. I was checking out the heavy duty impeller it does feel to be a bit stiffer but the cost is an additional $25 each. If you need the kit it gets a bit over the top! I am going to do the same I will monitor it next year and if all is well with the plate seals etc I will invest in the heavy duty impellers at that time.

We should get about three years with the kit is what I am told. Doesn't hurt to check on it. My impellers are over due by a year, so I feel it's a must before the start of this season. They probably would work just fine but why risk it.

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