2004 Mercury 115 2 stroke - oil injection block off plate

[griggsmars]

Hello, I would like to remove my oil injection from 04 Mercury 115 EXLPTO 2 stroke outboard. The motor is on a pontoon boat that I always fill with gas cans. I have been having an issue with oil leaking from the holding tank and think it would be easiest to simply block off the oil injection and mix the fuel. Does anyone have any advice on this option and if they know what block off plate to purchase and how difficult the job is. Thank you, Mike,

 

[Boats Pal Marine]

If you’re looking to block off the oil injection on a 2004 Mercury 115 2-stroke, you’ll need a simple oil injection block-off kit/plate. Mercury used oil injection on those motors, but a lot of owners choose to remove it and premix their fuel for peace of mind.

• The block-off plate itself is just an aluminum plate (usually sold as a kit) that covers the spot where the oil pump mounts.
• You’ll also want to remove the oil pump and gears, then install the plate with the proper gasket or sealant.
• Kits are available from aftermarket suppliers like Boyesen, Pro Marine, and on sites like eBay, Amazon, and many marine parts stores. Search for “Mercury 2-stroke oil injection block off kit” – they’re usually under $30–$50.
• Don’t forget to plug or cap the old oil line fittings and run the motor on 50:1 premix after the conversion.

It’s a straightforward job if you’re comfortable with basic wrench work, but follow the service manual for torque specs and proper sealing.

 

[Texasmark]

I have done that to two engines, 90 and 115 Mercs. All I did was to unscrew the oil pump and remove 1 of its hoses (so that I could pull it back), pull it back, remove the gear/drive shaft...easily removed just grab it and pull) and put things back. left oil in the tank as it wasn't bothering anything. Since you have a leak, then drain the tank mox-nix.

Oh spending a good portion of my life with pre-mix I was accustomed to doing that. When internal oiling systems came out I got used to not premixing. After the above mentioned modification, I wrote the premix ratio adjacent to the fuel filler so that I wouldn't forget.........

 

[griggsmars]

Thanks for the replies. I ordered the block off kit and hope to do the install next week. Thanks again for the info. Mike

 

[Scott Danforth]

I would look to see what is leaking. could be something simple.

 

[flyingscott]

The 3 and 4 cylinder mercs had goid oil injection systems. No reason to delete them.

 

[Texasmark]

The 3 and 4 cylinder mercs had goid oil injection systems. No reason to delete them.

1. I don't know what gold means...having had both of those (90 and 115) mine showed no signs of any gold.
2. As I got older I boated less and less. As a result when it was time to start the engine at the launching ramp. the starter would turn the flywheel and in the process ensured that oil was being delivered to working parts.

Well apparently there wasn't a lot of gas finding its way up the hose to mix with the oil that was being delivered and that may be due to the crappy primer bulbs that are available these days....for a root cause! They don't suck up the fuel and get hard like the old diamond shaped Merc. bulbs did.....and that includes the Merc./Quicksilver little packets of bulb and short lengths of grey hose.....for $35.00 at WM no less!!!!!!!! The (newish) one I removed I cut open because it felt resistance when apparently there wasn't fuel being sucked up and inside I found a separate liner that was causing the resistance I thought was fuel being sucked up.

So......the engine is getting a lot more than 50:1 oil in its gas. Finally the engine decides to start and you'd think the engine was on fire for all the smoke. I'm blaming the bulbs because I didn't used to have this problem on initial startups. After that initial start the engines would start before you could let go of the key!

I Disabled the oiler, installed an electric fuel pump, put premix in the tank and problem solved. Instant starts......same engine, nothing in the engine has changed other than the oiler deleted, only change was how the fuel was sent to the engine on initial start ups.