SMOKE!

[CarlW]

Ah spring... hope I didn't screw up!
My tried & true 50hp Force outboard ('93 or '94) is now smoking out the water ports. Whitish-colored smoke. What's that mean?
It wouldn't idle w/out stalling so I put some seafoam/drygas and mixed fuel to it at a fast idle for about 5-10 minutes. No smoke for a little while, then smoke. I thought the smoke might be loose gunk and carbon fouling plugs, etc.
Pulled plugs and they are clean as I've ever seen them.
Motor starts right up even though smoking. It will almost idle on it's own. WTF? Thanks.

 

[GA_Boater]

How much Seafoam and is it still in the tank? A heavy Seafoam treatment will fog the neighborhood for skeeters.

 

[CarlW]

Used a one-liter soda bottle as my "tank" for the cleaning. I put about 3oz of seafoam, 3oz of Heet (red bottle), then rest of liter bottle mixed fuel plus some added oil for good measure.
This was after adding seafoam to main tank, so YES, seafoam still in main tank.

 

[Jiggz]

The fact the plugs are clean and it smokes white it usually means there is water intrusion into the cylinder(s). You might want to do a compression check to see which cylinder is leaking water.

 

[CarlW]

Thanks. I hope I didn't starve the motor of oil during the seafoam treatment. Might the water intrusion you mention be due to a gasket failure instead? I have since drained out the seafoam mixture and am using fresh mixed gas. The white smoke is still there only less so. Engine stll will not idle. Probably a carb cleaning is needed.

 

[Jiggz]

Do the compression test first to get it out of the way.

 

[CarlW]

I tore my Tillotson carb down, gave it a rebuild kit and cleaned and compressed-aired everything. The carb looked fine inside, not a real mess or gunky at all. New gaskets installed, etc.
I put it back on and fired her up. Motor stars right up, but still won't idle. I have to keep throttle advanced almost all the way, Motor runs somewhat uneven and I know the rpms are not as fast as should be.
Another forum said turn/screw in my mixture screw a bit... this helped smooth her out but she still won't idle.
White smoke is largely gone. Plugs beginning to blacken as normal (they were clean as a whistle after seafoam treatment.)
Anyway, I let her idle for a while...boat is at the dock and in the water. I managed to throw her in gear quickly and took a short ride (5 minutes). Motor ran much smoother under load and I had it almost wide open for a time.
I returned to the dock and to my surprise she idled long enough for me to tie her up, but I could tell she was struggling.
I shut her down and went to get more fuel as I was almost out.
When I got back, motor started right up but still won't idle.
Any thoughts as to what's going on?
Fuel pump?
I did notice fuel sometimes forms a drop on the underside of my fuel bowl and I think I saw fuel coming out of the front of the carb when first starting it.
Thanks for your suggestions.
Have not done a compression test as I do not have a tester. Thank you.

 

[Jiggz]

It's very important when you decided to adjust the fuel air mixture adjustment screw that you do not go below I turn out from lightly seated. In fact, I highly recommend you do it 1 1/4~ 1 1/2 until you figure it out what makes it not idle smoothly. You need to find out where the fuel puddling on the carb's underside is coming from. Is it from the little vent hole on the side of the carb or is it from the "mouth" of the carb. If it is coming off the mouth of the carb this could be an indication of a bad reed. While if it is from the vent hole, it could mean a bad float or needle valve in the carb's bowl causing the semi flooding of the carb.

 

[oldboat1]

think I would work at getting a compression tester (screw-in type). Maybe you can borrow one -- rent one?

Is it pumping water? I take it you are spraying a good amount of water out of that port on the leg, along with some of that exhaust smoke. Temp on the top of the head shouldn't be too hot to touch -- shouldn't be over 160 if you have a temp gun to check (running temp around 130/140F would be good).

You may need a head gasket, which is not a big deal, although broken bolts are a hazard if it's a salty. Also, wouldn't be a bad idea to check for water if you have a permanent tank (draw up a sample from the bottom, and let it settle out in a glass jar -- fuel will float on the top if there is water.)

 

[CarlW]

Thanks... I wonder if I should just get a new carb. Found one online for $125. Might be easier than messing with variables.
I know it's not overheating. I can touch the top of the cylinders when it's running and plenty of water pumps out the leg. Smoke was likely just from seafoam treatment. It's not smoking anymore.
Plus, I think this wouldn't effect anything when it's first started as it would be cool then. She won't idle when first started... motor sounds very normal. Not a lot of heat emanating off it, etc.

 

[CarlW]

And I will get a compression tester. Good to know the state of the motor there.
My gas tank has no water present. It's a portable tank and i completely emptied and washed it out then let it dry in the sun with no cap for a few days. Fuel bulb, line and filter are new.

 

[Jiggz]

I would not recommend replacing the carb at this point until you know for sure what is causing the rough idling. What you need to do is to get a paper and pencil to write down all the symptoms you can gather why it idles rough. For example, fuel leaking at the vent hole on the carb, max rpm at wot and also max speed, at what rpm does "roughness" starts to smooth, etc. Have you installed a clear fuel filter between the fuel pump and the carbs' inlet? You should to help you with your troubleshooting. You can just use walmart's Fram G2 fuel filter for less than $5 and it even comes with hose clamps.

 

[ferdly1]

These carbs are bad about fuel bowl coming loose. Make sure fuel bowl is tight on bottom.

 

[CarlW]

I would not recommend replacing the carb at this point until you know for sure what is causing the rough idling. What you need to do is to get a paper and pencil to write down all the symptoms you can gather why it idles rough. For example, fuel leaking at the vent hole on the carb, max rpm at wot and also max speed, at what rpm does "roughness" starts to smooth, etc. Have you installed a clear fuel filter between the fuel pump and the carbs' inlet? You should to help you with your troubleshooting. You can just use walmart's Fram G2 fuel filter for less than $5 and it even comes with hose clamps.

Thanks Jiggz for the suggestions and for mentioning how much to back the idle screw out.
This is a real no-frills boat, no gauges for RPM test, not even temp or fuel gauge.
Can you explain where this "vent hole" on the carb is where fuel may be leaking from? (see link to diagram).
And by reed are you referring to #31 on diagram linked below?


If so, how do you get that little plug out right above said reed?
And yes, have an aftermarket fuel filter, but it is placed right before fuel pump. And it's new. Thanks again.
And thank you ferdly for mentioning the fuel bowl comes loose on these carbs.

Mod EDIT

 

[Jiggz]

No #31 on your link is not the reed. If you want to see what the reeds looks like go back to that link and then click on Reed Plate and Adapter Flange. As for the vent hole follow this thread which shows a pic of a carb and its vent hole, albeit the carb style might be different but it will give you a general idea what it is.
http://forums.iboats.com/forum/engi...9877-interesting-post-about-force-carbs/page2

The aftermarket fuel filter before the fuel pump is not necessary as there is already a screen filter at the inlet side of the fuel pump. The clear fuel filter between the fuel pump and carb inlet is more for troubleshooting fuel related problems than filtering. Clear filter so you can visually see if the fuel pump is delivering right amount of fuel or if there is any leak before the filter with the presence of bubbles.

 

[jbcurt00]

Please remember that Iboats is an online retailer in addition to being the generous host of this free to use forum and refrain from posting links to competitor sites.

 

[CarlW]

Thank you. I cannot see where to click on "Reed Plate and Adapter Flange" on that original link. And found the vent hole. Nothing leaking.
Some recent developments:
Just read another thread where the poster said gas was running out the front of his carb. Someone had an insightful reply for me about needle valves: there are two types. I looked at mine and seems the rebuild kit I got had a solid needle whereas my original was rubber-tipped. I guess it's no wonder I had gas leaking out the front...
I put my old needle back in (looks in good shape) and the motor almost ran at full RPM. It surges and wants to but won't. No more gas is coming out my carb front though. Things seemed to have improved a bit, but it still won't idle....
I plan on getting the comp tester tomorrow.
Sorry for posting competitor links. Won't do this anymore. Cadet mistake.

 

[CarlW]

No #31 on your link is not the reed. If you want to see what the reeds looks like go back to that link and then click on Reed Plate and Adapter Flange. As for the vent hole follow this thread which shows a pic of a carb and its vent hole, albeit the carb style might be different but it will give you a general idea what it is.
http://forums.iboats.com/forum/engi...9877-interesting-post-about-force-carbs/page2

The aftermarket fuel filter before the fuel pump is not necessary as there is already a screen filter at the inlet side of the fuel pump. The clear fuel filter between the fuel pump and carb inlet is more for troubleshooting fuel related problems than filtering. Clear filter so you can visually see if the fuel pump is delivering right amount of fuel or if there is any leak before the filter with the presence of bubbles.

OK, tinkered some more with her and I am still in the same boat, hehe
And now I know what a reed is!
Did a compression test. Happy to report 130psi in each cylinder and they held that number without dropping.
I no longer have gas leaking out the carb front and no drops under bowl.
Taper on mixture screw is nice and smooth. I set it at 1 and 1/2 turns out. It seems to run worse at 1 and 1/4 out. No change between 1 and 1/2 and 2 turns out. I am keeping it at 1 and 1/2.
[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]And I got a clear Fram G2 fuel filter and put it between pump and carb. It lays horizontally and gets about 1/2 full. Hard to tell if any bubbles are there as it's vibrating a lot. I thought I saw small bubbles a time or two but not really sure...[/FONT]

Some insights:
Top plug is blackening normally, while bottom plug is clean, a little too clean I think.
Not sure what to make of my current situation. Motor always ran great, tried & true.
Think a reed is still the cause? No vapor or smoke from carb mouth when shutting off motor.

 

[Jiggz]

There are only two known reason why a plug will be clean as a whistle with a running engine. Either it is not firing or it has water intrusion that is steam cleaning it. Since you have good compression the most like cause of a clean plug then is that it is not firing. Double check you have spark and fuel going into the bottom cylinder. If there is spark then do the wet paper test.

Remove the bottom plug, hold a white sheet of paper in front of the plug hole a few inches away (4-6 inches) and crank over the motor. If there is fuel going into the cylinder it will spray into the paper and should get it wet after a few cranking. If not then, fuel is not getting into the cylinder. If there is wetting and not sure if it is enough, do the same test on the top cylinder and compare. The amount of wetting should be about the same.

 

[CarlW]

No Title

There are only two known reason why a plug will be clean as a whistle with a running engine. Either it is not firing or it has water intrusion that is steam cleaning it. Since you have good compression the most like cause of a clean plug then is that it is not firing. Double check you have spark and fuel going into the bottom cylinder. If there is spark then do the wet paper test.

Remove the bottom plug, hold a white sheet of paper in front of the plug hole a few inches away (4-6 inches) and crank over the motor. If there is fuel going into the cylinder it will spray into the paper and should get it wet after a few cranking. If not then, fuel is not getting into the cylinder. If there is wetting and not sure if it is enough, do the same test on the top cylinder and compare. The amount of wetting should be about the same.

Thank you, Jiggz. I think you've honed in on my problem. I am almost certain I am running on just the top cylinder, and I think it's the ignition side of the equation.
Now wonder it won't idle on just one cylinder.
Did both spark and paper test.
Cannot report conclusive spark findings:
I laid spark against block and cranked her over, but nothing on either cylinder. I then bought a pen-style tester with a light inside that I place on each wire while engine running and that showed nothing ??
So, with engine running, I removed top plug wire. Motor died.
When I switched things and did that same test by removing just the BOTTOM plug wire, nothing changed. She kept running.

Paper test for fuel delivery showed the BOTTOM cylinder is receiving far more gas, which is odd as that plug is squeaky clean.
Top cylinder shows hardly any fuel spray, but this is the plug that is blackening normally.
Anyway, I removed the blue plastic block where the BOTTOM plug wire originates thinking I might have a bad connection or fray, etc.
The plug wire on back of the block looked ok, but the small wire off said block had a bare spot... aha! I thought....
I cut it and placed a butt connector over it and re-assembled everything.

When I fired her up she almost ran normally, almost... It didn't last long and I was back on a "half RPM" kind of situation.
And I am noticing a sheen of gas on the water around the dock. Must be the unburned fuel from BOTTOM cylinder.
Boat starts right up with only top plug wire attached. No luck with only BOTTOM wire attached. Just cranks.

Attached is a pic of my ignition setup. What parts might I need?
Not sure of the exact year. I thought it was always a '93-94 50hp, but a carb diagram from 1990 is more accurate than one from '93-94.
Motor number on transom bracket is 1400-819128. W3 is right under the longer number.
Thank you!