The Mystery inline update

[kblackav8or]

So far I have been tinkering with this motor for about 2 weeks. I started out just figuring out the wiring. Moved into replacing ignition wires and plugs. That was enough to get it running. Next steps have been to pull the lower and rebuild the water pump/impeller. I managed to get it apart without much drama. Things had been cared for. All the hardware had some sort of anti-seize on it. Prop came off easily and then went back on once I discovered the manual leads you through full disasembly of the lower end along the way to the water pump. Not to fear that was the only un-needed step I did. Water pump impeller had seen better days. Replaced it, the top of the pump (didn't really need it) and approprate gaskets. Ran into a hiccup putting the lower back on in failing to engage the shift shaft properly and after some help and extra tries got it back on right. Shifts properly and where it should. Neutral right in the middle of the travel. Hooked up the water and decided to test the water pump. Was more fussy starting this time. Mostly due to lack of battery power. Hooked it up with another battery and it was running and pumping water as it should. All the cylinders seemed to feel like they were at a matched temp. Still has some fine tuning needed. Carbs probably should come off for a good cleaning. Might wait on that to see how it runs with the lower submerged in a can with plenty of water so it can be revved up a bit.

Mercury Tower of Power inline 6 outboard running with new water pump impeller installed - YouTube

I am building a service stand for it and any other motor my brother may obtain which will make running and working on it much safer and easier. I will have pictures of it shortly. Still waiting on the parts needed to bolt it up to a transom.

 

[emckelvy]

Re: The Mystery inline update

Yeah, you need to get it in water, at least halfway up the exhaust tower, to get some back pressure on it. Then you'll be able to get a decent adjustment on the carbs.

If the barrel you use is stout enough, you can even idle the motor in gear and get a real good idea whether all cylinders are hitting or not.

Mechanically, the powerhead doesn't sound "thrashy", so that's a good thing. But it doesn't really sound to me like it's hitting strongly on all (6) cylinders.

Could be something as simple as a carb idle mixture adjustment but hard to tell.

One good way to tell what's going on, spark wise, is to clamp your timing light around each plug wire, in succession. You'll be able to see right away whether that cylinder is firing consistently.

If you don't have a timing light, most auto parts stores sell an inexpensive "firing indicator" which will have a neon bulb for the telltale. Not as bright as a timing light, so best checked in the dark. BTW, running at night is a good way to check plug wires for arcing/sparking. "Leaky" wires will light up like a Christmas tree in the dark!

Carb-wise, if you set up a small spray bottle with some pre-mix, you can spray a little fuel into the carb throat. If rpm picks up, that carb isn't fueling properly (or just needs idle mixture adjustment). If it slows down or dies, then at least you know that carb was actually doing something.

Once you get your barrel setup, idle 'er in gear and see how she sounds. The exhaust back pressure and prop loading really make a difference in tuning. Things you'll never hear when running on a flusher, will crop up right away in the bucket.

HTH & keep on pluggin' away, you're doin' good so far!........ed

 

[canoemang]

Re: The Mystery inline update

It does sound ok..

You do a comp test yet?

 

[kblackav8or]

Re: The Mystery inline update

I haven't been able to find my compression tester. Not sure there are funds to deal with a powerhead with a low cylinder any time soon. I should be able to get it on it's new stand and in some water in the next few days.

 

[canoemang]

Re: The Mystery inline update

Most parts places will loan you one for free...

 

[Scott Danforth]

Re: The Mystery inline update

any auto store will loan you the compression tester