1978 Evinrude 85 Hp has black soot coming from lower unit

stevemad

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Joined
Jul 13, 2013
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I was having trouble starting my 1978 Evinrude 85 hp outboard motor for a month or so. I never really got it to start properly. I would pump the primer till its rock hard, turn the key and push it in to activate the choke while cranking. It would never start right away. A couple days ago, while on the lake it was hard to start but ran a few times for 5 or 10 minutes even at WOT and ran pretty good. On the last run, it sputtered at low idle, the engine quit running and would not restart. A couple days later, I cleaned the throttle plates a little bit and disconnected the fuel line while cranking thinking that it was possibly flooded. I checked and found really strong spark. I did not try any starting fluid as I have read that it's bad to do that. Well it started today but smoked like crazy. While it was smoking heavily it ran like it was very rich on fuel, I'm assuming from the seafoam cleaner????? Then I noticed the black soot from the lower unit. I had the flusher hooked up while it was running and had a steady stream coming out of the cooling "telltale" hose. After seeing the soot, I disconnected the fuel line and ran all the fuel out(in less than a minute). I am obviously going to take it in to a boat shop once I find one that is reputable, but does anyone have any ideas..I posted a link to what the soot looked like here:

http://db.tt/TGws7w40
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

Seafoam is a good fuel system cleaner. Likely the seafoam attacked some of the normal soot/tar that covers the inner exhaust tube. When some of the soot dissolves it winds up coming out of the prop. A normal situation. You need to confirm that the choke solenoid is actually closing the choke butterflys in both carbs. You will have to remove the outer airbox cover to see the choke activate. That engine's a bear to start if the choke is not working properly.
 

Otte

Petty Officer 1st Class
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Jul 26, 2011
Messages
273
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

I had that happen when I did a carb cleaning before getting the boat out this summer. Black junk came out the exhaust and smoked like M. Jackson when his hair caught fire. My carbs got really messed up because el cheapo (me) ran a tank of old gas two years ago and I have been slowly getting back to normal with the engine.

Edit - I knew nothing of outboard engines before joining the iboats forum. I am still learning and not even close to being an expert. However, don't feel like you have to run it in to the shop to fix the engine. Buy a $25.00 repair manual for your make and year and spend a bit of time reading here. You can fix stuff yourself. Many of the marine mechanics I have met are solid people and very willing to help but they need to make a living so they charge appropriate rates. I just have a tight budget so need to do much of the work myself to stay on the water.
 
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stevemad

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Joined
Jul 13, 2013
Messages
6
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

You guys were right, the seafoam cleaned up some carbon and that's what I'm seeing come out. I wen to a local boat repair shop and the boat he had running was doing the same thing. Thats def good news. I'm now going to do a compression check to find out why it's running so bad. I started it back up to get all the gunk ran thru and it seemed to clear up only a little bit. When I disconnected the fuel line to run it out of gas, the idle went very very smooth, likr it should be until it quit?? Weird? Maybe the oil/gas mixture isn't right. I put 4oz with 2gallons?? Thought that was right?? Anyone know how many screws should be in the fuel pump cover? Mine is missing one and there is a little residue of gas in that area.
 

emdsapmgr

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Joined
Dec 9, 2005
Messages
11,551
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

The two strokes love to run lean. When you disconnect the fuel line, right at the end (when the carbs start to run out of fuel) the engine rpm's will pick up. Maybe quite a bit. You noted the difference. This is normal when you pull the fuel line. Leave your carbs jetted just the way they are to keep the powerhead from scuffing the pistons/cylinder liners. Your fuel pump cover has four short screws on the cover. The two outboard bottom screws are much longer and are used to mount/hold the pump to the side of the block.
 

stevemad

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Joined
Jul 13, 2013
Messages
6
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

Ok...I found the manual choke lever opposite the choke solenoid, was stuck closed. As soon as I freed it, the idle went smooth. So I guess that along with me choking it too much led to all these problems.
 

kjdunne

Petty Officer 1st Class
Joined
Sep 22, 2007
Messages
370
Re: 1978 Evinrude 85 Hp has black soot coming from lower unit

Good to see you got it running better. Many times it's something very simple. Get the factory manual for your engine and with all the knowledge on this forum, you'll be able to fix almost any common problem.
 
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