Yamaha 1987 V4 115 HP Water in Gearbox

[ozkor]

Hi My gearbox seems to operate well but after changing the oil renewing the washers on the drain plugs etc and about 3 hours operation the oil is all milky again.

I have been told that redoing the seals on these gearboxes are not simple at this age. Is it worth getting it fixed or should I just allow the motor to go until the gearbox wont work or is it worth getting it fixed. The motor goes like the clappers (70kph) and has equal compression on all cylinders except a 5% difference in number 4 cylinder. The contols are a bit sloppy and I need to get them either serviced or replaced.

Would appreciate any opinions on this. I may have a go at doing the seals although I have never done anything like this before.

Thanks in advance for advice or opinions.

 

[racerone]

Changing oil seals on a fresh water motor is not hard to do.-----Repairs are usually cheaper than waiting for major damage to occur.

 

[robert graham]

Must be either the prop shaft seal or the driveshaft seal or the shifter shaft seal(since you already replaced the drain/vent plug seal/washers). The driveshaft seal and shifter shaft seal would be easier to replace than the prop shaft seal(since that bearing carrier may be stuck in there with corrosion and a challenge to remove)...I'd pull the prop off and inspect that seal for fishing line maybe wrapped around shaft and causing the seal to leak. An outboard shop can run a simple pressure test on the lower unit to determine which seal is leaking and replace the bad seals for you....a whole lot cheaper than a new lower unit or a new outboard. In any event it's not all that of a major deal to get a seal replaced....Good Luck!

 

[DangarStu]

These gearboxes can fail pretty suddenly and catastrophically, so if you do decide to run it until it fails you will risk needing a tow home. You may not get any warning. Here's a little vid I did on making a home-made pressure tester for the seals. If you enjoy that sort of thing it might be worth your time to figure out which one is the culprit. It is possible to remove the prop shaft seal without removing the bearing housing but you need to be careful not to scratch the shaft as you will only tear the new seal up straight away if that happens.

http://youtu.be/Lzn-nshSlwk

Stu

 

[ozkor]

Thanks all for your advise I will look into doing a my own pressure tests and if need be get a mechanic to look at changing the seals.

Thanks again for your input it been really helpful.