Mercury OptiMax Fuel Pump Clean Out

Our Mercury OptiMax 115 is again having problems with fuel delivery. In this video, I'll disassemble the fuel pump and vapor separator tank, clean everything, reassemble and test the engine once it is re-installed. I'll let you know along the way which parts do what, and some things to watch for.

[@peterogryzlo5675]

Thank you, and thanks for your attention to detail. The gasket on the outlet to the HP fuel pump has failed twice on my 115. I never would have attempted a repair without your video.

[@adriandavies2941]

Rich I really appreciate the level of detail you provide walking us through this. I suspect my 90hp Optimax needs this done. It struggles to idle when i first start up but after getting it in gear it settles in and no more issues all day.

[@masterbaiter1704]

Thank you for this very informative video!

[@MohdAbbas123]

Very useful explanation, thank you for sharing this video 👍🏻

[@banksy000]

Great detail in this video, Thanks

[@9volts25]

Thank you for a very informative tutorial

[@FreshFraser]

Thanks for this video. Saved me some serious hassle!

[@EricsBBQAndMORE]

Another great video. I'll be sure watch again before I have to clean mine out again.

[@RichBrownsChannel]

Awesome! Thanks.

[@barbozasilva5083]

Excelente ..muito bom

[@JoeTayMetal]

I have a 2006 225 Optimax. I have fuel leaking out of my lower unit all of a sudden. Don't notice the leak inside cowling and only does it when its running a few seconds before it dies. Can a bad diaphragm or pump cause this?.

[@barbozasilva5083]

Muito bom

[@josephrensch9401]

I had to replace my high pressure pump and now it will not start. Did you have to do anything to bleed air?

[@RichBrownsChannel]

there is a fuse on the passenger side of the engine for these motors. check that first. if that's ok, open it back up and make sure the power is properly connected to the pump motor.

[@maritimeus]

I have a 2004 Mercury Optimax 115hp on my 1996 Mako 19’ (just bought the motor with the boat). There is no fuel priming bulb (I checked). Before I do this maintenance on my optimax, how should I ensure the motor is primed when I reassemble? Because there’s no bulb, should I assume that the optimax fuel pump will self-prime? It must not have been a problem for the previous owners and marine mechanics. Any suggestions or ideas for the procedure? Thanks

[@RichBrownsChannel]

A primer bulb is easy to install. Buy one at Academy or a marine store. Cut your fuel line a couple feet before it gets to the engine. Make sure it will sit where you can reach it easily. Stick the primer nipples into the fuel line, making sure the “flow direction arrow” is pointing toward the engine and tighten the clamps. Done.

[@maritimeus]

@@RichBrownsChannel I appreciate the reply, but are you able to please answer my original question? Do the optimax engines self-prime? If not or unsure, then I’ll be happy to follow your advice above and install a priming bulb. Thanks!

[@RichBrownsChannel]

@@maritimeus my boat came with a primer bulb, which I rarely use. Don’t know if it will self prime.

[@nathanmiller9087]

How did you hook it up to a 12v source ?

[@RichBrownsChannel]

I used jumper wires with alligator clips. Just connected them to the boat battery

[@brian3.2]

Can I mail you mine and have you rebuild, replace or clean my entire vst?

[@RichBrownsChannel]

ummm, no

[@twistedjigco.548]

@@RichBrownsChannel it’s a lot of time consuming tedious work.

[@muzikmanernie]

Are these Optimax good motors and also better on gas as far as between EFI's? I'm looking at a 2006 175hp Optimax that I want to buy

[@RichBrownsChannel]

I've had lots of fuel delivery issues with mine. If I was going to buy another outboard, I'd go with a Yamaha four stroke.

[@wheninrome42]

hows she running nowadays bud

[@ericelmer5289]

So when I have my OptiMaxx, idling or in gear, but not given any, guess it will eventually quit. Starts up fine, but right away sputters. At higher speeds I don’t notice anything. Do you think I should be doing what you were doing and what was it that you found as to why your motor wasn’t working right?

[@RichBrownsChannel]

If mine was doing that, I’d check the filter, replace if dirty. Then put a bottle of Seafoam in the gas tank, and a little bit in the oil tank. Then put it in the water and drive around for a few hours. That’s what I would do with mine. I’m sure there are Seafoam haters that want to rip me a new one. Don’t waste your time on me

[@ericelmer5289]

@@RichBrownsChannel I checked the gas tank no leaks. Then I checked the fuel pump. Both are good. I think the air filter or whatever it is could get changed. I got my hoses and everything to the primer bulb hooked up squeeze it a couple times it started leaking from the hose from the primer ball to that then smaller hose that gets hooked inside. If there was a small air leak where the hoses join together could that give me my problems?

[@ericelmer5289]

@@RichBrownsChannel ok so I cleaned the water separator pinch the bulb and where the top of the separator is the valve on top of it the one towards the middle. What does that go to cause hooks up to a hose connect and is now leaking gas

[@RichBrownsChannel]

@@ericelmer5289 umm.., Elmer, I’m not sure what you are asking. There is a drain at the bottom of the VST under the filter, used for draining water. Use an allen wrench to tighten the allen screw

[@ericelmer5289]

@@RichBrownsChannel I got that all figured out but just tell me this. On the far right side down at the bottom next to where you can put a gauge to check the pressure that line going into the VSP if that seal isn’t in there right that could reduce the flow right or let air in?

[@xuxothao7199]

So did it work?

[@RichBrownsChannel]

Everything in the fuel pump and VST worked. After reassembling, I also found a small, but significant leak in the fuel pump vacuum hose, right at the lower clamp.After that was replaced, the motor ran perfect for 30 minutes, in gear and at 2000 rpm.

[@dangerously72]

@@RichBrownsChannel 2000 rpm? My Ranger w/200 Optimax Pro XS won't even stay on plane at 2000 rpm...I usually cruise around 33mph @ 3000 rpm.

[@marcelobesen4067]

friend makes video. to remove thermostatic valve

[@stewatparkpark2933]

Sounds rattly . Check the compressor .

[@dangerously72]

Definitely Rattling....