2008 8.1 horizon raw fuel in exhaust

[wjglampe]

New boat to me. Just noticed on start up, very black soot then raw fuel in exhaust, stbd motor. It keeps spewing raw fuel while running. Motor starts and runs fine, nothing in oil, anti-freeze normal. Any suggestions? Cool fuel unit??

 

[Zorba]

Most likely you need spark plugs. I don't have the raw fuel but I am running extremely rich on my port motor and burning +\- 10% more fuel. I'm due for plugs.


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[wjglampe]

Thanks for the suggestion but I'm pretty positive that's not the issue. This raw fuel poring out the exhaust. Engine runs fine.

 

[mainstream]

Wires and plugs you won't know that the engine is running fine unless it's hooked up to a scan tool I had same issue the computers try to keep engines running smooth try reaching max rpm I had a tech in ER while running he had scan tool monitoring engines as rpms went up he could see miss firing on a couple cylinders changed wires and plugs all good since.

 

[wjglampe]

I don't think wires and plugs are going to poor raw fuel out the exhaust in large quantities.

 

[mainstream]

How much is large are we talking a sheen on surface or just smell I had a small sheen when it ran and if you cool fuel is messed it won't run right at all I have same boat and had same symptoms if the wires and plugs have not been done I would start there

 

[wjglampe]

It is a LOT of fuel. Mixed with the exhaust water. Engine runs normal. I can't run it (wont) because of the amount.

 

[mainstream]

Like I said unless you hook a a scan tool you won't know if it's running normal the only way fuel is getting into your exaughst is it's not firing or you have and open valve which would cause no compression so I would call a mechanic if you don't think it could be a ignition problem where a couple of cylinders are not firing you can not go by the tachometers just my .02

 

[wjglampe]

Does anyone know if the gen iii cool fuel unit failed internally like the raw water exchange, would put extreme amounts of fuel out the exhaust?

 

[rondds]

I have not heard of a CF3 failing internally. They leak (into the bilge) at the raw water fittings (problem I now have) and there are problems with the painted inner fuel chambers.

My boat ran up to 3k RPM with the plug wire OFF the #1 plug. Only noticed it when I got up on plane and the boat was not "behaving" like I am accustomed to. The computer does and awful lot of compensation to try and make things right. "Pulling a code" might clue you in to the problem.

 

[wjglampe]

I ordered 16 plugs and 2 filters today. Marine Max also told me that more than likely a plug. Doing all of them just so I know what I got. If it turns out to be plugs, I owe mainstream an apology.

 

[rondds]

Buy yourself a set of WOBBLE extensions and a spark plug boot puller. Will save you a lot of swearing. I hope you have plenty of room in your ER.

 

[Ididntdoit]

Yes - one of the ones I removed on my boat had just started to fail to the inside.......I think its a real possibility your cool fuel 3 is the problem - remove the fuel pressure regulator thats on the unit (not the rail) and I bet you'll see evidence - or hook up a fuel pressure guage to the rail - I bet your pressure is high.....While my boat was not as bad as yours, you could smell/see how "rich" one side was running.....when I had the oil sampled, there was gas in it too.....

 

[wjglampe]

All 8 plugs were black as coal. Do you think replacing all of them will resolve my issue or is something else wrong that would cause all of the plugs to show a "rich" condition and raw fuel/black smoke in exhaust? I will be installing new plugs today. BTW this happened after running several hours at a "no wake" speed (1000 RPM) due to restrictions. Soon I will be able to power up and see what it does.

 

[rondds]

I've heard that these 8.1s are notorious for fouling plugs. Do you know how long they've been in there? My boat was very hard to start cold and I changed the plugs and that problem went away. I do think it will solve your problem, but what the hell do i know? LOL. One way to tell. Run the girl!

 

[wjglampe]

Replaced all plugs. My suspicions were confirmed, still raw fuel in the exhaust. Pulled the vacuum unit off of the cool fuel unit and waa laa water and fuel mixture. Ordered new gen iii cool fuel module tonight. Dead for the weekend.

 

[rondds]

Installing my new CF today. I'll let you know how that goes. What did you pay for the one you ordered?

 

[wjglampe]

Did you get the one off eBay for $103? I ended up buying one from Doug Russell marine. $299.
Do you know how the fuel line from the gen iii to the rail is removed from the gen iii?

 

[rondds]

Bought a whole new unit from THIS place. Pretty easy job. Access is great on this boat. I can sit btwn the engines and work on it. Just have a headache from gas fumes.

 

[rcmafgny]

The cool fuel should be $800 - $1000

Did you get the one off eBay for $103? I ended up buying one from Doug Russell marine. $299.
Do you know how the fuel line from the gen iii to the rail is removed from the gen iii?