got smoke coming and strong fuel smell at startup

Ethan's Tank

Ethan's Tank

Member
Jun 1, 2014
425
aquia creek.potomac river United States
Boat Info
2009 Searay sundancer 350DA with twin 496 seacores
2000 wellcraft 2600 martinique [old]
Engines
Mercruiser 350 5.7 EFI
The last 2 times I started up my boat at cold start, my boat creates a slight smoke screen from the stern under the swim platform. Also a very strong fuel smell. I'm not sure if this is the engines warming up, but I tried trolling for about 10 mins at 600 Rpms and I still get it at low speeds. When I cut the engines off, I see a small trail of fuel in the water. Is this normal or something I should worry about? Also the small exhaust port holes has nothing coming out of it, just looks like the smoke is coming out from underneath the stern. My engines are 496 seacores
 
On my former 8.1's, whenever I smelled raw fuel on start, it needed plugs. I don't recommend the AC's any more. Use the Champion cross-ref'd plug...It's been posted here.
 
So I have a new issue. I anchored out for about 30 mins right outside my marina and the starboard engine (with the raw fuel) wouldn't start up. Smart vessel retired start sequence aborted and fuel injector error was displayed. Limped back to my slip with 1 engine and no power steering
 
sfergson727 said:
Change the spark plugs. 8.1's are killers of plugs. I doubt it's an injector issue, but the cheapest route is to try the plugs first. If that doesn't work, it's time to hire a mercury authorized mechanic with a CDS computer. There's too many potential killers in these engines to piddle around with, not worth the risk.
Click to expand...

I'll see if I can get some tomorrow... U think that may help it ? Seems like th engine is flooded with fuel, although not carburetor ed
 
sfergson727 said:
Yeah, my buddy with a 340, just had the same issue. Changing the plugs took care of it. The mercury certified tech told us that the 8.1's are notoriously hard on plugs. I had a similar issue last year along with vibration, changing the plugs fixed it.
Click to expand...
Thank you very much...hopefully that fixes it.
 
The flaking paint in the cool fuel 3 module will give you the same symptom. As the FPR gets plugged up with paint, it will make the fuel pressure spike.
 
2009 should have CF4, though Merc still painted the inside of the CF4s so anything goes I guess.

I found perforation in my old CF module due to galvanic corrosion. Can this cause fuel to get into the exhaust? I did NOT have any fuel odor in the exhaust.


Start at Post #46
 
Is there a way to check for the flaking paint in the FPR? How do you know you've got this problem?
 
Zorba said:
Change your plugs. It easy and cheap and odds are it will fix your issue.

http://clubsearay.com/showthread.php/68005-8-1s-Spark-Plug-Replacement-DIY-with-pics
Click to expand...

Thank you very much for the link, that would be most helpful. So I went down to the engine room and poked around, the boots were all pretty much stuck on each one or my arthritis has kicked in and I have no strong grip anymore [I am definitely going to purchase that boot puller driver on that DIY link]. I managed to pull a few boots off and I definitely cannot not see down there to save my life. My engine room is huge, but the way they space these engines is tight. I had to finger around to make sure everything was back in order, I snapped a pic of each plug to make sure it was all the way down. So I came back up and let the bilge fan run with the hatch open for 20mins before I attempted to start any engine.
First time - no good
second time - no good
third time - I decided to videotape the RPM on smartvessel for my records. No good and I forgot to press record
fourth time - I was hesistant since it may be messing with something in my engine, but made sure this time I press 'record'. It cranked up

I let it run idle for about 5mins. started the port side engine and that was fine. Fuel smell was still strong, but no smoke. So I decided to turn off both engines, pack up the truck [30min for that chore] and try it again. I left the bilge pump on the whole time. I was trying to mimick what I did on sat evening when I was limping back to my slip.

After about 30mins, I started the engine and it started right up, and there was some faint fuel smell, but not strong and no smoke. I am still worried to take the boat out in case I get stranded and limp home on one motor for 10miles and/or just wasting fuel. Even still just messing up this boat in the long run without properly fixing the issue.

The other thing that bothered me, was I noticed that same engine [starboard] gear oil reservoir was low in gear lube. Would that happen if I was limping home on 1 engine and no power steering. When I was limping home, I really had to turn the wheel to make any type of adjustment to my boat. I am thinking maybe since I was running on 1 engine, the dead one was trying to turn as well due to its mechanism, and I may have broke some seal and leaking gear lube or something else....
 
sfergson727 said:
If they serviced the gear lube when you bought the boat, it may have just burped. Fill it back to the full line (but don't over-fill it) and then monitor the level. Usually what happens is you fill the drive by hand pump via the fluid drain hole. Often that leaves an air void in the line from the drive lube reservoir to the drive. After a while, that air pocket works itself free and the fluid level will appear to drop.
Click to expand...

fingers crossed, my last boat I had the lower unit serviced and it kept needing a fill up. When they surveyed that boat, the dealership said the lower unit needed to be re-hauled ($5k).
 
The corrosion on the lower carrier bearing that occurs on B3 can cause the drive to spit gear lube under torque but it doesn't allow water to come back into the drive.
 
MancaveII said:
Is there a way to check for the flaking paint in the FPR? How do you know you've got this problem?
Click to expand...

Check your fuel pressure at the rail, should 38psi at idle. Mine was at 70. There are 2 screws that hold the regulator to the cf3, pull it off, and you will see the paint
 
So I emailed Mercruiser about the issue and the part numbers for the plugs, here is the reply:

We're sorry to hear this happened to your engine. The fuel injector fault and smell of raw fuel seem related, the wet fouled spark plug may be a result of this and not a cause.
Please have this issue inspected by an authorized MerCruiser dealer right away.
They need to hook up to your engine with a laptop loaded with G3 software to troubleshoot the fuel issue.

The spark plug is 863622001 or AC 41-983.

Anyone know what the G3 software is or had this done, I'm wondering if its a mercruiser diagonistic tool or chvevy tool in general?
 
Interesting timing...I have this, just came in two days ago, but I cannot figure out where it plugs in. The likely cables in the rear of the engine, do not match up. I have the connectors for the ECM and CAN.
 
My plug is labelled "DIAGNOSTICS". There's a cap in the end of the plug. You have to pull the cap off. First time I thought I had the wrong cable but didn't realize the plug had to come off first. Pull off the plastic shield on top of the motor.
 
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