1999 Mercury 135 Optimax Outboard Engine on 2040-parts.com

Engine Specifications

• 2.5 liter V6 two stroke
• 25" shaft (standard, right hand rotation)
• Electronic Direct Fuel Injection (DFI)
• Oil injected
• Compression per cylinder 120 +/- 5 lbs, same as the spec for a new engine (1-115,2-125,3-125,4-125,5-125,6-120)
• 308 original engine hours
• Power trim and tilt
• Uses the “7 pin” Mercury engine harness (actually, 8 pins, but they don’t count the center pin, don’t ask me why)
• FYI, there is a crankcase port below the No. 1 piston that connects to a pressure hose that feeds crankcase pressure into the external oil tank (pressure in the oil tank is used to feed oil to the engine through a second hose.)  Because the crankcase has this pressure outlet under the No. 1 piston, compression readings on the No. 1 piston are always a bit below the other pistons on new/newer engines before variability sets in (the engine uses a small amount of compression from this cylinder to run the oil system.)
  About This Engine
  With only 310 hours, this engine is just broken in.  It was part of a twin setup on a boat that was stored inside for a very long time and then new four strokes were put on when it was finally sold. 
  Prior to removal from the boat, this engine was inspected and hours/compression read. This motor is in top running condition with like-new compression.  
  There is light damage to the cowling. 
  This engine is an original, low hour, never rebuilt or reworked engine.   Beware of "rebuilt" two stroke motors.  Optimax 2.5 V6 engines should run in excess of 2000 hours without issue. Premature failure occurs for a reason, usually because of restricted fuel feed, a stuck ring, defective oil injection, etc. (lack of proper inspection/maintenance).  Something causes an engine to experience premature failure; engines don't fail prematurely for no reason.  The powerheads are often rebuilt and the engine is sold without any understanding of why it failed, so the problem remains, causing new damage and another premature failure of the engine block down the road.  Also, engine assembly is very important for reliability (bolt torque, part clearances, tolerances, etc.)  You want a motor that is factory assembled, not assembled in a garage by who knows who.  Many rebuilders reuse worn parts, don't use torque wrenches for all bolts, don't properly shim for clearnace, and don't verify tolerances, etc.  The motor for sale here has never been touched except for regular maintenance. It was built, assembled by Mercury and has run reliably ever since because it was properly maintained.  I have the maintenance records since it was new for the winning bidder to review.
  
  
   About V6 DFI Two Stroke Engines
  If you know V6 DFI two stroke engines you know they are lightweight, high performance machines with thrilling performance that the four strokes just can’t deliver.  Just ask the tournament bass fishermen why they use two strokes. 
  Both Yamaha and Mercury have made their V6 DFI two stroke motors in two versions: small block and big block.  All of the recurring problems that Merc and Yamaha had with their V6 DFI two stroke engines were in the big block versions (3.0/3.3 liter, delivering 200+ HP, as much as 300 HP).  Two stroke technology is just not a good fit for high HP, big block engines.  If you need that much HP, you need a four stroke (sorry, thrillseekers).  The small block V6 two strokes have been great, reliable engines for both manufacturers. 
  This engine is the small block 2.5 liter version sold by Mercury in the Optimax and Pro XS series, with power ratings of 135 – 200 HP.  The secret to buying V6 DFI two stroke engines is to buy the small block engine, like this one, and also, to buy the low HP version.  A low HP rating means less stress on the engine/more reliability.
   The 135 Optimax is the lowest HP rating for a Mercury 2.5 liter block; it has been an outstanding, reliable, bullet proof engine.

• This motor is listed locally as well. I reserve the right to remove this listing at anytime. 

• If you have any questions, please let me know.