Mercury Black Max not going above 2000 rpms

jonnyfish

Petty Officer 3rd Class
Joined
Nov 28, 2016
Messages
79
The motor is a 135 merc black max, late 80s or early 90s, not positive.

I'm hoping to get some feedback on what may be going on with my motor. This weekend was the first time getting her on the water since last year. Last year she was a hard starter at times, but no real problems so to speak.

I fired up the motor on muffs friday, and a bunch of gnarly gunk spit out when it fired up. I checked the lower unit oil and it was milky colored. Bad. I drained the lower unit oil, and replaced with new oil.

Fired back up and ran on some gas with sea foam, everything seemed good.

Put the boat in on saturday morning, fired it up and a huge billow of white smoke came out, I thought maybe it was burning some old oil, once that burned off again it seemed fine.

As I took off from the landing the motor seemed to be struggling for gas, I reached back and pumped the bulb, it was soft, so i pumped it up again. At this point I started to put the throttle down, none of the power i expected or am used to was there. It would not go above 2000 rpms, and I had to pump the bulb once more before it seemed to stay hard.

Once at the dock after about 10 minutes of driving I trimmed motor up, I noted some oil seemed to be leaking. when I trimmed it back down, a huge plume of oil came out of the exhaust, the motor was not running mind you. I did not run the motor again until I needed to get it off the lake, as I motored it back I noted the same things. When I fired it up, lots of white smoke burning stuff off, it also spewed out a ton of green looking gunk from the exhaust, that I did not think was oil, but I am unsure.

As a note, I've only used non-oxy gas with this motor, however I've only owned this motor a year, and while the P.O. said he used non-oxy premium only, who can truly say.

Here's the kicker, as I get back to the launch, and am in neutral I think that the motor sounds slightly different, I get it to the dock and kill it, there is a mechanical type of burning smell, I'm not sure how to describe it but its that smell where you know it is not a good thing.

After I get the boat out I check the oil tank, EMPTY! After it was close to a gallon when it was put in the water, there is no way I did enough boating in 20 minutes at 2000 rpms to go through that much oil. And what frustrates me more is I got no warnings that the oil was out! When I fired up the motor all was well, status beeps were per usual, so that is not out.

Prior to getting the boat out of the water, the running theory was that the carbs may be severely gunked up, and that I should check the fuel line (which is new mind you) and the fuel line connections.

However, now I'm more terrified, I plan to call a marine mechanic and get further consultation on what may be going on, but I'd like some opinions from all of you, have any of you been in this situation? Any ideas on what might be going on with my motor based on what I've described? Is it completely fubar after the oil running out.

Are there some simple things I can check to get hints on what may be going on with my motor, before potentially sinking in money.

Thanks.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,119
Check the fuel pump diaphragm, for holes. Obviously look for leaking 2 cycle oil. I think I would start mixing oil with the gasoline at 50::1 ratio, until you get this sorted out.

Take a compression and spark test to rule out engine damage.
 

jonnyfish

Petty Officer 3rd Class
Joined
Nov 28, 2016
Messages
79
Thanks for your response Chris1956 . I'm going to start by checking compression and spark, to confirm there is no engine damage. If everything is good there, i'm going to try and run it on muffs and see if i can locate where the oil may be leaking from.

Is there an easy way to disconnect the oil intake and just do the premixed gas? I've read about this update before, and I'm really frustrated I didn't go through with it, because this is the exact situation a guy wants to avoid.

Hoping I didn't blow up the engine, a friend who did this on a vehicle by accident said I may be in the clear as I wasn't running the motor hard when I heard that noise and then noted the oil was out.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,119
You remove te oil pump, pull outthe drive gear and reinstall the pump, with the oil hoses connnected in a closed circuit. The exact procedure is avail on this forum, likely in the top secret files
 
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