Smoooke on the Waater

[Trés 30]

(dun dun dun, dun dun dudun)

After a long trip down a short rabbit hole I've got the engine running pretty good (& lookin nice).

The issues I'm having trouble diagnosing are:
1- Smokey exhaust (PCV kit installed)
2- High Idle
3- High Op Temp
(all without load)

Timing seems to float to the top after some consideration. Any thoughts on this appreciated. I don't have a tach or temp gauge, so 2 & 3 are "by feel".

[the backstory (optional)]
Just as a means of thinkin out loud here for possible causes of each:
1: -Dirty fuel- it's non-ethanol gas, been in the tank 6-8 mos. But just
installed a new seperator/filter and polishing filter. Will try fresh gas
-Bad rings (not a lot I can do at this point, but please no)
-Too rich (a problem I've never had) -leaned out w/ idle screw
(seated then backed 1.75 turns)

2: -Adjusted idle screw (happy medium I hope)
-Could adjusting main jet help this? & is Carb removal necessary to
adjust? (no adjustable main jet kit)
-Timing could be adjusted (retarded?), but seems to be firing smoothly

3: -All Exhaust after manifold is new, so no obstructions there. Water
leaving thru-hull with good force. Will do an acid flush to
improve overall circulation.
-Also wondering if routing water from therm housing to aft (instead of
fore) manifold fitting helps

[hanleyclifford]

Without a tach and temp gauge you're going to have a problem with rpms and temp issues. Are you FWC or RWC?

[JOHN COOKSON]

A couple of thoughts to get things started.
Clamp the bypass hose and see if the temperature drops.
Ditch the PCV valve until things get sorted out.

TRUE GRIT

[Trés 30]

I'll give those a shot

I'm RWC, will put gauges & sending units on the list, & try to get more scientific in my approach

I'll try closing off the PCV for the moment. Which gets me thinking, the only thing I really changed doing this little overhaul was the scavenge tube. Possibly related(?) PO had a pretty large (1/4" ID) hose clamped on for the scavenge tube. I put on an 1/8" copper tube on the fittings, so likely changed the vacuum quite a bit.

Will report back on how it goes.

Thanks much!

[Al Schober]

Tres,
As to the smokey exhaust, are you getting any smoke in the cabin? If so, that makes the rings suspect. What's the overhaul history of the engine? The rings do wear out, and the oil control rings seem to go first. As to the mixture adjustment, the idle adjustment controls AIR. Screw in = less air = richer. I'm a fan of the adjustable main jet. Besides adjusting the mixture, it also allow you to clear a lot of main jet clogs without disassembly - just screw the needle in, then screw it out.
As to temp and RPM, sounds like you're just guessing. I'd recommend an infrared thermometer ($20 at Harbor Freight) and a dwell/tachometer from your local auto parts store.
Feeding into the low end of the manifold would affect engine temperature. All that will do is purge any bubble out of the manifold (certainly not a bad thing).
Best..

[hanleyclifford]

If you are running hot with RWC and you have a thermostat you should get the thermostat out of there. Going to the Thatch Modification (reversing connections on the manifold) is a good idea if for no other reason than you will get to inspect those passages. Good idea to lose those 90 degree fittings in favor a straight pipe to barb.

[67c&ccorv]

PCV kit only masks the real problem - that your rings are worn and allow the engine to burn oil in the combustion chamber.

[Trés 30]

Al,
I am in fact getting smoke in the cabin, so rings a possibility (I'm praying against it), but may be a poor exhaust connection. I cranked that pipe til my elbows hurt putting it together, to no avail. Overhaul history is mostly unknown before I got it, though there is some rubbery gasket material/sealant squeezed out between oil pan & block, making me think a more serious overhaul was performed.

I made some adjustments today and got far less smoke in the exhaust, as well as slowed the idle some. Temp still "seems" high (good guess about my guessing ) Will head to harbor freight soon.

Adjustments included:
-decrease flow through therm housing (to get more flow to block)
-disabling PCV (this & above suggested by Mr. Cookson)
-reset points gap (was way too wide)
-advancing (?, counter clockwise) timing slightly when running (this really brought RPMs down)
-adjusting idle screw (after clarifying, yes, it controls air)

Here are a couple videos of today's performance:
Exhaust Exiting Thru-hull
Engine Running in Cabin (aka: the smoking section)

Thanks all for the input!

[67c&ccorv]

Re: the smoking section;

...is there a crack in your manifold threaded section - seems like exhaust gas is coming out from the threads???

Is your mixture properly adjusted - I can't tell if I am seeing "oil smoke" or "rich mixture" smoke in either video?

[Al Schober]

Can't tell if that smoke is coming from the threaded joint or from the 710 cap. Try removing the cap and plugging the hole temporarily, then see where the smoke comes from.
End gap on new rings is supposed to be less than .010" - I did a 'smoky' engine once where the oil rings had an end gap of over .100". Those rings were just going along for the ride!

[Trés 30]

I got the exhaust smoke down to an acceptable level, even less than in the video, so maybe just a mixture adjustment. Cabin exhaust does seem to be coming from between the threads on the flange (?) though the pipe & flange are new & tightened as far as it will go without blocking the port for measuring pressure.

Overall smoke in the cabin is less than previously and I'm hoping that smaller leaks in the joints will seal themselves, as I've read they can do. Here's hoping (that I don't have to entirely redo hot section). Tach/dwell meter & IR thermometer coming soon!

Thanks again!