Mercury 280

[MUFC777]

I just purchased a boat with a 1999 Mercury 280 on it. The engine started fine but I'm wondering what other things I should do or should I get it serviced by a mechanic.

[Frank Molé]

if it dosnt have top pinned pistons,it needs them................

[MUFC777]

Is that it?

[Jay Smith]

Top pinned pistons, Injectors serviced by Brucato and TDR reeds, upgrade to the NGK BPZ 8H N 10 spark plugs... Kickin combo...

Jay

[MUFC777]

I live in Bermuda so I'm guessing all this would involve me sending the motor to the U.S. I was wondering if there was anything I could do myself to ensure the motor is in good condition. I've heard of the Leak Test but I'm unsure if anyone locally performs this test.

[Jay Smith]

A 280 is IMO not a motor to try and "learn on" unless your very versed with these engines I'd let a professional do the work. We build and ship motors around the world, shipping a power head is no big deal we recieve and or ship 2-3 a week...

Jay

[MUFC777]

I've already identified one problem which is the prop shaft. It's twisted at the end and needs to be replaced.

[fatboy0484]

what is the stock compression on a 280? and what compression should you rebuild the motor at and also what all needs to be done in the rebuild?
just rings?

[CUDA]

I thought 280's came with top pin pistons? leak down will tell you most about rebuilding , main thing about compression is the #'s be close to each other, there should be someone in Bermuda that should be able to handle everything, sounds simpler to me to stay on your home turf, ask around about local high performance marine mechanics , there is usually someone that is respected by many through past dealings . A lot easier in the long run. Offshore is ruff on prop shafts.

[Jay Smith]

Fact is 280's did not start coming with Top Pinned Pistons until AFTER serial number :

0T 430855 ( 2001 )

I have built a stock headed 280 with fresh Nicom Plate job and new rings and have witnessed 162- 165 lbs cranking on all holes at sea level...

Leak down should be from 4 to 8 % then I would think about a re ring job unless you want an $800.00 re plate job added to the rebuild costs..

My .02
Jay

[MUFC777]

Can anyone tell me the part # for the Prop Shaft for this engine?

[mach351]

44-840451 A03 fat shaft standard sporty

[MUFC777]

I need the small shaft.

[mach351]

Small shaft NLA - good luck

[MUFC777]

How much fuel pressure do I need for the 280?

[--mirage1--]

You have a 39lbs regulator

[Greg G]

After Merc made the top pin upgrade in 2001 where there any further substantive changes after that model year until they stopped the 280 in 2005?

[RBT]

Rods were changed to big
heads were changed
propshaft
reed cages

not sure on any of the years that this was done