2000 Speedster w/ Merc. M2 V6 2-stroke 240hp Smokes like a Chimmney!!

[Garrett303]

To start out, im a newbie boat owner. Ive seen a few threads on here about the subject but nothing specifically addressing this exact model and engine, at least that I have found. Just bought it, all the boat shops in my state wont work on it, have to drive to Ogallala Nebraska for the nearest possible mechanic. Not that thats an issue but if it's something fairly straight forward that a mechanically inclined person like myself can possibly tackle than im all for it! I was able to download the exact model of engine's owners manual and there's a few things im going to check out first from that but I would really appreciate you guys if you could point me in the right direction. Or if you know of a mechanic in the Denver metro area that will work on this that is also very much appreciated.
Some of the symptoms include the following:

1. Excessive white smoke at idling speeds that disappears at higher throttle.
2. That's it for the smoke issue. Can add further details with your questions.

The boar runs great otherwise and sounds great too. This thing flies when the throttle is pushed out! The smoke is something that is just concerning as of right now but i know this isn't a normal operating thing.

Also, the fuel gauge does not work and the speedometer works intermittently. Checked the fuses and wiring harness's. Nothing glaringly wrong with those. Any help on diagnosing those problems would be awesome as well.

Thanks again. Let me know if you need some pics or other info. Will probably take it out to Chatfield Res. on Sunday so i can post some pics or look for other symptoms that you guys ask for.

 

[Garrett303]

So i know about the linkage issue, cant seem to find that exact spot. Here are some additional pics of the port side.

 

[paulc229]

Are you on premix, or running the oil injection system?

 

[Garrett303]

It's the oil injection system. Was thinking of taking it out and trying to drain the gas out of and replace it with straight 87 and see if that helps. I have no idea if the previous owner put pre-mix and also ran the oil injection simultaneously and thats what I'm seeing.

 

[CURT7TY14]

Any luck on this issue? My 01 is having the same issue.

 

[Tim75]

All 2-strokes smoke some. The larger the engine, the greater its capacity to smoke. You have a fairly large 2-stroke.

Have you checked all the small hoses around the crankcase? These take pooled fuel and move it so it can be burned. The rubber hoses get brittle and crack. Also intrducing vacuum leaks. I use weed-eater fuel hose as replacement. Have the injectors ever been serviced? After all, they are 20 years old.

Back to the oil pump. Looking at the pump, throttle at idle. Arm on pump should be at 9:00 position. Should move with throttle.

 

[OUTOFTHEBLUE77]

To start out, im a newbie boat owner. Ive seen a few threads on here about the subject but nothing specifically addressing this exact model and engine, at least that I have found. Just bought it, all the boat shops in my state wont work on it, have to drive to Ogallala Nebraska for the nearest possible mechanic. Not that thats an issue but if it's something fairly straight forward that a mechanically inclined person like myself can possibly tackle than im all for it! I was able to download the exact model of engine's owners manual and there's a few things im going to check out first from that but I would really appreciate you guys if you could point me in the right direction. Or if you know of a mechanic in the Denver metro area that will work on this that is also very much appreciated.
Some of the symptoms include the following:

1. Excessive white smoke at idling speeds that disappears at higher throttle.
2. That's it for the smoke issue. Can add further details with your questions.

The boar runs great otherwise and sounds great too. This thing flies when the throttle is pushed out! The smoke is something that is just concerning as of right now but i know this isn't a normal operating thing.

Also, the fuel gauge does not work and the speedometer works intermittently. Checked the fuses and wiring harness's. Nothing glaringly wrong with those. Any help on diagnosing those problems would be awesome as well.

Thanks again. Let me know if you need some pics or other info. Will probably take it out to Chatfield Res. on Sunday so i can post some pics or look for other symptoms that you guys ask for.

I have the same issue with a 2001 challenger mercruiser. I found that the oil pump was off alignment so had it adjusted. The smoke at idle was basically gone but still present on throttle. We then tested the TPS and it wasnt getting the proper voltage. I am currently waiting for the part to arrive and install. Hopefully that is it because the TPS are expensive.
Ill post the outcome

 

[Rookie_MIB]

Also, the fuel gauge does not work and the speedometer works intermittently. Checked the fuses and wiring harness's. Nothing glaringly wrong with those. Any help on diagnosing those problems would be awesome as well.

I might be able to help you with this - I have a 97 Challenger XP which had the same issue. Ultimately, my problem boiled down to the fact that the way the fuel gauge works is a float with a magnet goes up and down inside the fuel tube which sits inside the fuel tank. There is a PCB inside the tube which has a bunch of reed switches (magnetic) and resistors. As the float goes up and activates a switch, the cumulative resistance changes and the system uses the resistance to determine where the float is.

There are a few ways for this to fail. One - the float goes bad and gets filled with fuel and sinks. Replacement is easy - you loosen the rubber sleeve sealing the tube to the tank, label and remove the fuel lines (assuming carburetted boat... fuel injected might be different), there's a screen on the bottom of the tube which snaps off and the float would just come right out. Replace and put it back together.

The other way it can fail is more difficult - the PCB has a 250ma fuse built into it, and the PCB is not removable. I fixed mine by clipping the two wires, drilled two new wire holes on the top of the tube, cut a window where the fuse is, removed the bad fuse and soldered a wire bridge in place. Fed two new wires in, soldered those to the main terminals, and put in an EXTERNAL fuse. Took some plastic-weld and sealed the window back up and smoothed it out.OEM design is about the worst I've ever seen. Easiest way to test for this is to disconnect the wire at the connector which is near the front of the bilge hull (firewall in car parlance), use a multimeter to measure the resistance. If it reads an open circuit and no reading then you have the bad fuse.