Smell raw fuel while running

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savanahrae
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Smell raw fuel while running

Post by savanahrae »

Those of you who watch this forum probably already know this but I recently bought a 1985 Trojan 10 meter with Crusader 454's and I'm slowly working the bugs out of it. We took her offshore this weekend and the whole time we were running I could smell raw gasoline from the cockpit. I checked all lines and connections and found no leaks. It seems to be much stronger on the starboard side. Is it possible that the engine is not burning all the fuel and I'm smelling it from the exhaust? One of the reasons I came up with that idea is at low speeds the engine seems to load up with fuel and I have to rev it up to get it running smoothly again. Any thoughts?
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Post by jimbo36 »

First off!! If I'm smell'in raw gas the last thing I want is engines running. The second last thing would be to be off shore! You need to find the problem BEFORE starting her up again. :shock: jimbo36
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Post by rossjo »

Jimbo is right! Do not start or use the boat until you solve this ! Use your bilge blowers before even turning on lights, etc. You might even disconnect the shore power until its solved just to be safe.

Ethanol (mandated by our Govt, pretending to be Engineers now) is often the culprit.

I have another rebuild scheduled for the QJet on the 454 in my 26 Chaparral this weekend. I have to do it at least once per year, because the ethanol in the gas destroys the seals.

Are your 454's carbed or FI'd?
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RWS
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Post by RWS »

this is SERIOUS.

Do not start the engines again until you find the problem.

Every year PEOPLE DIE due to explosions/fires caused by raw gas on boats.

DO NOT TAKE THIS LIGHTLY.

Start with a CLEAN towel, wipe in in suspect areas and then sniff it directly.

Here's one from last week.
EGG HARBOR TOWNSHIP — A marina owner was killed Friday afternoon when his 30-foot cabin boat exploded, caught fire and sank, State Police said.

Gary Theno, 51, owner of the Hidden Mill Marine Center, was at his Thompsons Lane facility when the boat exploded at about 2:30 p.m., State Police spokesman Sgt. Stephen Jones said. His body was recovered at about 5:30 p.m., and he was pronounced dead at 6:55 p.m.

The victim might have been working on the boat or on a nearby dock when the explosion took place, Jones said.

“We’re not exactly sure what he was doing and where he was at the time of the explosion,” Jones said.

The marina is near the Great Egg Harbor River in the Scullville section of the township.

Ron Kennedy, a resident along nearby Somers Point-Mays Landing Road, was washing his car with his wife when he saw thick, dark smoke rising from behind a thicket of trees.

“My wife wondered if it was a tree fire, and I told her, ‘No, it’s not a tree fire,’” Kennedy said. “I thought it might be a house on fire.”

Firefighters sprayed the fiberglass boat, which melted in the intense heat, as dozens of fire personnel watched from a nearby dock.

More tanker trucks were called to the scene later in the afternoon, and firefighters put out the fire and inspected the damage. Only the metal railing at the bow of the boat remained intact.

The marina was closed for the winter, but boat owners could make an appointment to come to the site to work on their craft, according to the message on the marina’s answering machine. A second branch of the business, on the Black Horse Pike in Folsom, has some limited winter hours.

Egg Harbor Township Mayor James “Sonny” McCullough said Friday night, “He was a hard-working, great marine mechanic, well-known in the area.”

Theno is survived by his wife, Sheri, and two children, McCullough said.

Great Egg Harbor River Watershed Association administrator Fred Akers sat with Theno for several years on the River Council of the Great Egg Harbor National Scenic and Recreational River. Theno lived in Folsom but represented Egg Harbor Township on the council because his business was located there, Akers said.

“He had a lot to say about the river and the environment,” Akers said Friday night. “That was his business and his livelihood.”

Theno knew a lot about river issues, especially as they related to recreation and boating, and was knowledgeable about technical topics such as the waste that boats pump into the river and how changes in fuel affected boat engines, Akers said.

The cause of the explosion remained under investigation, Jones said Friday night. The State Police Marine Unit was investigating, assisted by the Arson Unit and Major Crimes.

Staff writer Michelle Lee contributed to this report.
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LandVF36
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Post by LandVF36 »

I concr with Rossjo. Ethonal is bad news on or old carbs. If you have electric fuel pumps, take the spark arrestor off the carb and shine a big flashlight down the throat of the carb. Have someone turn on the key to run and just bump it once. The pump will come on. Look for gas running down inside the carb to the manifold. Its not suppose to be, but the ethonal can eat up or stick and old float and it will no longer work properly. The gass will just keep running through.

Its a pretty safe bet that even if you don't see it, that is what is going on. If you replace vs rebuild, make sure you get a marine carb, not an auto carb. The Marine carb has an input for your fuel pump over-flow and different gaskets. The auto carbs are not sealed up the same way and can be a reason yor boat will go "boom".
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TADTOOMUCH
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fuel problem

Post by TADTOOMUCH »

Does it smell after shutdown or just when running. Sounds like a carb rebuild is in order. Send it out to have it rebuilt or buy two new ones. It is too hard to clean a carb totally unless you have the correct equipment to boil the carb. It only costs a few hundred dollars to do two carbs or about $1000 for two new carbs. Sounds like a float sticking open and letting fuel overflow the bowl of the carb. Look down the throat of the carb with the engine not running just after shut down and see if you can see wet throttle plate or fuel dripping from the jets. The plates should be dry and their should be no fuel flowing at all.

If the float level in the carb is set too high it will cause this problem too. Sometime people rebuild them and never adjust the float properly or misinterpret the directions and get it set too high.

If you have black smoke coming out of exhaust while idling or smell a lot of gas from exhaust then this is a good sign it is running too rich. Pull a plug and look to see if it is black , wet, or tan. Black or wet is too much fuel. Tan is good, white is either brand new or running too lean which I doubt.
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Post by Dan Faith »

If you have mechanical fuel pumps and the diaphram is cracked it could be putting raw gas to the flame arrestor. This would give you the raw gas smell when running and cause it to run too rich at idle. Very dangerous I would keep at the dock until you locate the problem.
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Post by k9th »

I agree with all of the above - make sure to check that there is no raw fuel in the bilge or in the engine compartment or anywhere else for that matter.

If you are clear on those items check your anti-siphon on the tanks. I know on mine I had a problem with these having crud in them and I was getting gas fumes from the tank vent out the side of the hull. The updraft would bring it into the cockpit.

just my 2c & good luck.
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Post by alexander38 »

same thing went on with me last year. Here's my fix, 2 new fuel pumps $125.00 and 2 rebuilt Q-jet carbs from Sierra $425.00 each. Sorry for the bad news. Keep your old carbs and have them redone and in stand by. :cry: corn gas SUCKS!
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Post by RWS »

a bad fuel pump diaphragm can also cause gasoline to get into the engine crankcase.

If your oil level is going UP and it smells of gas, that could be the problem.

When I got my 10 Meter the fuel pumpos were factory original.

I changed them out fast.

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jimbo36
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Post by jimbo36 »

Hopefully this is a longshot, but it happened to me. If you have a cylinder that lacks suffecient compression to fire (less than 70 lbs) the raw fuel entering that cylinder will find its way into the crankcase. You will smell it and the engine will run much the way you discribe. Check the compression. :cry: jimbo36.
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Post by Rodman »

jimbo36 wrote:Hopefully this is a longshot, but it happened to me. If you have a cylinder that lacks suffecient compression to fire (less than 70 lbs) the raw fuel entering that cylinder will find its way into the crankcase. You will smell it and the engine will run much the way you discribe. Check the compression. :cry: jimbo36.
Pull the oil dipstick see if you smell fuel in the oil.
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alexander38
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Post by alexander38 »

that is so true, but I bet its in the carbs, but a compression check is cheap. And easy to check.
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savanahrae
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Post by savanahrae »

Thanks for all the great advice. To those who sent safety suggestions, thanks and we were alreday on that path. I have checked a lot of things and consulted with a carb specialist and have determined carb rebuilds are in order. Am pretty confident this is the culprit.
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Post by gettaway »

did you smell gas in the engine room when you smelled gas or just in the cockpit?

If there is not gas vapor in the engine room, could the smell be coming from the fuel tank vent when you were out and shaking up the fuel?

I have had a similar experience with my diesel trawler, I could smell diesel and traced to the vent when i had been out and shook her up a bit...
just a suggestion
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