08' 250XS Air Compressor replacement

**bouyhead** · 05-30-2017, 08:07 AM

I'm a newbie to outboards so I'm trying to gather a little more info on air compressor replacement. Boat was running fine all day Saturday. Idling down the canal to visit a buddy the motor starts to chirp pretty loud. Now not knowing much yet about compressors I did run the boat again back to the marina and it seemed fine. I removed the compressor and took apart the lower half to find the needle bearing in pieces and the connecting rod egg shaped and ready to let loose. I did a lot of searching but still have some unanswered questions. I plan on flushing the oil lines and replacing the small filters the feed the upper and lower crank bearings.

1. How do check operation of the oil pump?
2. Does the new compressor come pre-oiled?
3. Do you need to put the motor into break in mode after this repair?
4. Do I need to send out my fuel rail etc. to be cleaned? The upper part of the compressor was intact.

5. If the compressor doesn't completely blow to smithereens can debris still get past the piston and contaminate the fuel rail? Again the boat ran fine back to the marina.

Is there anything I'm missing? Any comments or input is greatly appreciated.

Thanks

**XstreamVking** · 05-30-2017, 10:57 AM

Oil pump will operate when the computer is put in break in mode. You will see oil working thru the lines at the filters. Compressor is oiled when the pump cycles at beginning of break in mode. It should have some oil in it already? Def need break in mode for new comp. If it was running good you may get away w/o cleaning the injectors, Just a guess. Expert opinions better than mine here. How many hours on the compressor? Had you been cleaning the water intake screen going to it?

**bouyhead** · 05-30-2017, 12:47 PM

Originally Posted by XstreamVking

Oil pump will operate when the computer is put in break in mode. You will see oil working thru the lines at the filters. Compressor is oiled when the pump cycles at beginning of break in mode. It should have some oil in it already? Def need break in mode for new comp. If it was running good you may get away w/o cleaning the injectors, Just a guess. Expert opinions better than mine here. How many hours on the compressor? Had you been cleaning the water intake screen going to it?

Thanks for the reply. Hour meter on the Smartcraft gauge shows about 275. I got the motor used last Fall so not a ton of hours since. I'm going to hook up a Rinda Datacom tonight to verify hours. I have not cleaned the water intake screen yet but plan on doing so before I install the new compressor. Just trying to cover all the bases. From what I've read the Merc compressor doesn't have a great track record, just want this one to live a little longer.

**XstreamVking** · 05-30-2017, 01:02 PM

Newer ones are better and last longer. You need to clean the screen often. Maybe every 50 hrs and more often if you operate in crappy weed and shell infested waters.

**bouyhead** · 06-01-2017, 09:40 PM

Installed new compressor today. Checked water inlet screen and it was plugged halfway up the screen. Hooked up the flush hose on the back of the cowling and got a little more gunk. I also changed the small inline oil filters. The new compressor is delivered dry, and I was concerned about bleeding/priming the oil system. You can do this two ways. Hook up a scan tool and click on prime oil pump or put the motor back into break in mode via the shift control method. Besides going into break in mode for two hours run time it will also prime the oil pump. It was kind of neat, after initiating the break in mode with the motor off you could hear the oil pump run for about 45-60 seconds and watch the power head mounted oil tank drop about one inch. Made me feel pretty good that all was primed and ready to go! Boat ran great tonight. Posted this info for all the newbs. Like me!