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packman312
08-03-2013, 10:59 PM
Do you guys change oil at the end of season? I am 10 hours shy of change and wondering if I change early, do I also need to change it in mid Sept for end of season winterization? Thanks in advance!

Packman

thatsmrmastercraft
08-03-2013, 11:01 PM
It depends upon how many hours you put on it after the oil change. If it's just a handful, then no big deal. If you use your boat a lot, then you probably ought to change it again before winterization.

supreme112279
08-03-2013, 11:06 PM
oil and filter is cheap. and engine is not.....change it.

JRW160
08-03-2013, 11:21 PM
The end of the season change is to remove the acids that build up in the oil during operation. If you only want to change the oil once, I think you would be better off running the oil you have in there an extra 10-20 hours than you would leaving used oil in there all winter.

GoneBoatN
08-04-2013, 12:05 AM
Do you guys change oil at the end of season? I am 10 hours shy of change and wondering if I change early, do I also need to change it in mid Sept for end of season winterization? Thanks in advance!

Packman

To me it is a better plan to change the oil a little earlier in the season and once again at the end of the season. I've already did my first oil change for the season as I was getting near the end of the interval and we were taking the boat on vacation. I did not want to change the oil mid vacation nor did I want to run over the interval. Now I'm 20 some hours into the current oil. Since we typically run through October and sometimes into November there is a chance I will be changing the oil three times this year. As already mentioned, oil and filter are not expensive if doing your own oil changes.

thatsmrmastercraft
08-04-2013, 12:13 AM
To me it is a better plan to change the oil a little earlier in the season and once again at the end of the season. I've already did my first oil change for the season as I was getting near the end of the interval and we were taking the boat on vacation. I did not want to change the oil mid vacation nor did I want to run over the interval. Now I'm 20 some hours into the current oil. Since we typically run through October and sometimes into November there is a chance I will be changing the oil three times this year. As already mentioned, oil and filter are not expensive if doing your own oil changes.

Very good point. Cheap way to make the engine last.

FrankSchwab
08-04-2013, 12:16 AM
I like having clean oil in my engine over winter. I change it before the last trip of the season ( or change it and run the engine up to temp) to fully circulate the clean oil, then I feel better all winter long.

I suppose that, technically, the best approach would be to change the oil, then crank the engine with the plugs pulled for 30 seconds or so to get clean oil to all the bearing without any combustion by-products, then put new plugs in and call it done, but that's far too MCOCD for me.

/frank

thatsmrmastercraft
08-04-2013, 12:22 AM
I like having clean oil in my engine over winter. I change it before the last trip of the season ( or change it and run the engine up to temp) to fully circulate the clean oil, then I feel better all winter long.

I suppose that, technically, the best approach would be to change the oil, then crank the engine with the plugs pulled for 30 seconds or so to get clean oil to all the bearing without any combustion by-products, then put new plugs in and call it done, but that's far too MCOCD for me.

/frank

You may be on to something, as long as the fuel is shut down. Do-able on an injected boat......not so simple on a boat with a carb.

FrankSchwab
08-04-2013, 12:37 AM
You may be on to something, as long as the fuel is shut down. Do-able on an injected boat......not so simple on a boat with a carb.

Actually, it's probably easier on a carb boat. With the plugs pulled, almost all the intake air will come through the plug hole, meaning air with no gas in it. With no air flowing through the carb, no gas will get into the manifolrd. With an injected boat, you should probably pull the lanyard to disable the injectors; otherwise gas will get injected into the manifold (for TBI) regardless of the air flow.

/frank

thatsmrmastercraft
08-04-2013, 12:43 AM
Actually, it's probably easier on a carb boat. With the plugs pulled, almost all the intake air will come through the plug hole, meaning air with no gas in it. With no air flowing through the carb, no gas will get into the manifolrd. With an injected boat, you should probably pull the lanyard to disable the injectors; otherwise gas will get injected into the manifold (for TBI) regardless of the air flow.

/frank

Not sure if I agree on most of the intake air coming through the plug hole on a carb boat. With the small proportionate size of the plug hole compared to the intake valve, probably only 1/3 of the intake air would come through the plug hole. Now if you held a towel over the throat of the carb, that should make virtually all of the air come through the plug hole.

FrankSchwab
08-04-2013, 12:56 AM
I don't claim to be an expert, so don't listen to me.

But at the low speeds that you'd expect from cranking, plus the large restrictions on a carb at idle (remember that vacuum through the carb approaches 30 in Hg at at idle; how big is the gap around the butterfly valves at idle compared with the size of the spark plug hole?), I'd expect that 75% or more of the air in the cylinder would come through the plug hole. And, with such a low velocity of air through the carb, I'd expect the airflow to pick up essentially zero gasoline. So, I'd expect that the air in the cylinders would be essentially atmospheric air with no gas in it.

/frank

VP46
08-04-2013, 01:00 AM
Wait... how often should you be changing the oil again? Every 3000 miles or every 12 months? ;)


Seriously though I have put a total of 50 hours on the boat and only changed the oil once. How am I doing?

FrankSchwab
08-04-2013, 01:23 AM
Assuming that you don't have a brand new boat (if you had one, you should have changed oil early), I'd take a look at how many hours I expect to have at the end of the season since the last oil change.
If it's less than 60 hours, I'd just wait til the end of the season to change.
If it's more than 60 hours, I'd change it at a convenient time (even if early), then change again at the end of the season. But, that's just me.

If you asked Mastercraft, they'd probably say "Change it every 50 hours, or once a year, using Penzoil 15-40". And they'd be right.
If you ask the MCOCD crowd here, they'd say "Change it at 50 hours, using <my favorite oil, all the others ones suck>, then change it again at the end of the season". And they'd be right.

Choose whichever advice makes you happy, and get on with life.

/frank

thatsmrmastercraft
08-04-2013, 01:50 AM
I don't claim to be an expert, so don't listen to me.

But at the low speeds that you'd expect from cranking, plus the large restrictions on a carb at idle (remember that vacuum through the carb approaches 30 in Hg at at idle; how big is the gap around the butterfly valves at idle compared with the size of the spark plug hole?), I'd expect that 75% or more of the air in the cylinder would come through the plug hole. And, with such a low velocity of air through the carb, I'd expect the airflow to pick up essentially zero gasoline. So, I'd expect that the air in the cylinders would be essentially atmospheric air with no gas in it.

/frank

I guess I can't argue with that. May as well spray some fogging oil into the cylinders prior to cranking.