Merc 40 HP ; water in drive leg

[bullsi]

I am considering purchase of an older 1977 14.5' Boat with 40 HP Merc engine. When checking the oil in the leg about 1/2 cup of water came out prior to the oil. This boat seems to be in immaculate physical condition and has obviously been extremely well maintained and taken care of over the years. Engine actually looks nearly as a new one. The water was clear until the oil came out. The boat has been sitting, unused since 2003 and the current owner is selling due to her husband recently passing away and has put it up for sale. How concerned should I be about this water in the gear box oil? I have turned the prop and it seems very smooth . Any info or help much appreciated as I am relatively new to the boating world and am not sure what kind of problems or costs I may be in for with this water problem in the drive. Thanks

 

[andrewkafp]

Re: Merc 40 HP ; water in drive leg

The water may be a result of loose drain/fill screw or drain/fill washer missing or damaged, or could be more serious (Seals gone). The only way to know quickly is to have the L/U pressure tested, and this will pinpoint where the leak is coming from. You don't really want to buy a motor with water intrusion in the gearcase, unless you have the correct tools and knowledge of L/U repair.

 

[bullsi]

Re: Merc 40 HP ; water in drive leg

Thanks. Help is appreciated. I will check the washers on the plugs. Is the pressure test something that I can perform at the current location or would it be required to take the boat to a dealer for this to be done? I am not clear on the procedure for this test or how much pressure is used. I pressume that there are seals at the prop drive shaft and the shift linkage.

 

[Moody Blue]

Re: Merc 40 HP ; water in drive leg

Water is the lower unit is more common than you might think. Multiple sources of leakage - prop shaft seal, driveshaft seal, shift shaft seal, fill/drain screws. Most are simple to repair with basic tools, a manual and some general mechanical ability. Cost for parts is relatively low. If the prop shaft seal is leaking then it becomes more of an involved job requiring specialized tools and more technical knowhow. <br /><br />Pressure testing can be done at home but is best left to the professionals. If you do a search on this forum you will find previous discussions about pressure testing the L/U.<br /><br />You don't mention where you are located. If water has sat in the L/U over the winter months and frozen, it is possible that severe damage may have been done. Otherwise water is not that big of a deal IF the proper lube was used in the first place. Marine gear oil has special emulsifiers that blend with water to still provide corrosion protection and lubrication abilities whereas automotive blends do not.<br /><br />If the rest of the motor check out (compression test, test run etc) and the price is right I wouldn't pass up the deal because of water in the L/U if you perform a close inspection. Is it possible to have a shop take a quick look at it and give there evaluation ? Any friends or relative with any motor knowledge ?

 

[bullsi]

Re: Merc 40 HP ; water in drive leg

Thanks for your reply. I am in Saskatchewan and we get severe winters here. Not sure if that bit of water could cause damage as it was likely in there last winter. There should be ample room to expand I hope. I do have mechanical skills but little knowledge of boats. Hopefully its just a plug washer but understand that even if this boat motor has been meticulously taken care of, due to its age there may be seals requiring replacement. I have found out that this boat has been seviced once annually by dealer and as I said, very well maintained by appearance . I will check compression due to the age of it and usage of it over the years. What should I be expecting for a compression read on this to be considered in good condition and not requiring a rebuild yet for a while? Thanks for your time and help.

 

[Moody Blue]

Re: Merc 40 HP ; water in drive leg

Anything over 100 psi is acceptable. Higher is better of course. Most important thing to look for is consistancy between cylinders. If there is a variance of more than 10-15 psi then something is wrong. Be suspicious. AS far as the water in the L/U goes, I have heard of cases of major damage being done, even cracking the outer casing and or splitting the carrier retainer nut. Water creates immense pressure as it freezes.