Changing oil brand ?

[cliff seary]

In my 1997 challenger, 787 engine, I'm not sure what brand of oil is in there now, only about 3" of it in the tank and I would like to change to this MystikJT-4 Sea and Snow 2 - cycle oil, but I read that you can't mix oils, Is it really necessary to try and get rid of all this existing oil in the engine first, also been told 2 cycle oil is 2 cycle oil, and it won't matter, would it be OK to change brands? Thank you.

 

[Dr Honda]

I would. The old API-tc oils didn't always mix. I've personally seen reactions that turn oil into pudding. The reason is... the test to get the TC rating is the same... but the API people didn't care what was in the oil. Just has to pass the test. Personally... every used 2-stroke ski I've bough has gotten the oil system drained, flushed, and serviced before it ever hits the water.

But it's up to you... there is a chance that the oil you are putting in will mix. But to me... the hour or so of proper servicing far out weighs the potential of a roasted engine. Not to mention... it sounds like boat is new to you (since you don't know what oil is in it) You should service the oil system anyway.

 

[cliff seary]

I would. The old API-tc oils didn't always mix. I've personally seen reactions that turn oil into pudding. The reason is... the test to get the TC rating is the same... but the API people didn't care what was in the oil. Just has to pass the test. Personally... every used 2-stroke ski I've bough has gotten the oil system drained, flushed, and serviced before it ever hits the water.

But it's up to you... there is a chance that the oil you are putting in will mix. But to me... the hour or so of proper servicing far out weighs the potential of a roasted engine. Not to mention... it sounds like boat is new to you (since you don't know what oil is in it) You should service the oil system anyway.

Thank you for getting back so soon, LOL, I actually bought the boat new in 1997,it just hasn,t been used and the existing oil is probably a few years old, I believe it could be Shell Nautilus, not sure, anyway, where would I find the instructions to drain, flush and service the oil system? I will do it the proper way, Thank you.

 

[mikidymac]

Get a new oil filter too.

 

[Dr Honda]

No real instructions on it, since it isn't a normal "maintenance" thing. But it's good that you are the original owner. I will run down the list for you........


1) Drain out what you can from the tank. I would simply disconnect the hose going to the engine under the carbs. Yes... this will make a mess, so, get a shallow bucket to catch what you can, and a bunch of old towels ready.

2) Disconnect the hose at the oil injection pump. (Let it drain) At this point, you cut the in-line filter loose too. I'll assume it hasn't ever been changed.

3) There are 2 small hoses going from the oil pump to the intake of the engine. I'll assume these are 20 year old hoses, and are getting crusty. I would replace them with new tygon hoses. I'm guessing if you squeeze, and/or twist them... they will split, rip, or squish. Regardless, the original hoses will eventually fail. (time just kills them) They are held on with clamp bands... but I just replace them with small, high quality zip ties. If you have wire tie pliers, and wire... do a double wrap and a bent twist. These are low pressure so you really don't have to worry about them falling off.

3b) This is a good time to replace the rubber grommets in the oil tank if they are leaking. Also... if the tank seems dirty... a little gasoline can be sloshed around to clean it out.

4) Put in the new filter, and put the hoses back on the engine, and pump.

5) pour some oil into the tank.

6) Remove the bleed screw from the oil pump, and let the oil flow to the pump, and feed the pump hose. The 2 hoses going to the center of the engine will fill on their. When replacing the screw, make sure you have the little fiber washer on it, and DO NOT over tighten it. It's small, and you could break it. Just make it snug.

7) Pop the cover off the air box, and remove the mesh inside. (good time to clean it with a degreaser like super clean) Pour about an once of oil into each carb.

8) WITH A HELPER........ hold the pump arm to "Full", and have your helper start the engine. LEAVE IT AT IDLE !! watch the 2 small hoses, and you will see the oil pump up to the engine in 5 to 10 seconds. Once filled... turn off the engine. The oil you poured in will keep it safe.

9) Check for leaks. If it's good... top off the tank, and rest assured that the oil system is now fully serviced and will keep your engine safe.