Did I just blow an engine?
 

Took the catamaran back out today after doing some adjusting on the engine that was giving me issues yesterday. While testing to see if my problem was fixed the other engine began to start running rough. Not only was it running rough but it now blows black smoke when reved and even leaves a trail of oil in the water. Please tell me there are other possibilities then a toasted engine. It will still fire up and the oil pressure is steady and holding about 70psi. Oil looks clean and full

I would do a compression test and leak down. Odds are it will render better answers than you will find here.

Sounds to me, like your carb has a piece of junk in it, flooding the engine, causing black smoke, and raw gas out the exhaust. That will leave a trail like oil will in the water.

Black smoke is a ton rich. The extra unburnt fuel is leaving those marks in the water.

If carb'd - get the carb apart and see what is flooding it. Look at needle and seat first. Trash will stick that open.

FI - get it scanned / then if you havwe to ck fuel psi / ck for stuck open injectors.

Gen 5 502 carbrated engines btw

Sounds to me like you need to step back for a second with this boat, and spend some time working on it, before taking it out again, and possibly doing permanent damage.

I would, do a full tuneup, plugs, wires, cap, rotor, fuel filters, etc. Go thru the carbs, check/set timing, . Then, go back out on the water.

You ever feel like your being echoed. LOL. Look at the time stamps. He,he

well....you're just obviously 1 step behind.....look at your join date, and look at mine....I got you beat by 4 months! almost 11 years here? Where does the time go?

Yup. Nothing but schitty advice so far.:rolleyes:

I have done plugs, wires, cap, rotor, rebuilds on both carbs, complete fluid and filter changes all around and checked timing on both engines. The tanks were pretty nasty when drained the boat did sit untouched for 5 years. Debris is definitely possible.

Only takes a tiny piece of crud in the needle and seat, and it will keep pouring gas in the engine. Start the engine and look down the carb, for dripping gas at idle from the boosters or even vent tube

Dose it have a mechanical fuel pump, with the plastic vent line goins to carb?
Bad fuel pump flooding the carb.?

I'd say needle and seat dumping raw gas too. Had this issue once. It was a build up of that wonderful ethanol gas that I ran.

Make sure you change the oil after you fix the issue.
If your dumping all that fuel down the carburetor you are diluting the oil with fuel and washing down the cylinder walls and bearings etc.

Mark

You guys are very helpful. Carb was dumping way to much fuel fouling my plugs and causing the engine to run so terribly. Thanks for the input

Do the carbs have chokes on them? If so, and the chokes/choke is stuck closed will cause a overly rich/flooding condition as well.

Just something easy that noone else said yet.

now see why it was.....like if it was needle and seat like I had once, there was a small peice of fuel line sticking it, replace fuel line to carb..... it will happen again, because if it clogs good you can lean it out and burn it up....

just rebuilt carbs. don't get stuck in the mindset-"i just fixed that. it has to be something else." you could have missed a detail, or a new power valve had a very short life or something like that.

My point was, do the basic stuff first before someone had him chasing down a faulty kill switch or some other nonsense.

You just can't expect this level of quality advice to come out this fast all the time.

I would put a good inline fuel filter before the fuel pump.

change the oil NOW or you can kill the engine with the oil contaminated by the fuel...

Yeah and depending on how contaminated the potential for blowing of the oil pan is there...

Are you guys playing "Jeopardy"?

BZZZZ "Alex, I'll take common marine engine performance issues for a thousand." :D

Speaking of which, the other night I had this vivid dream that I was on Jeopardy, and boy was I cleaning up. I was beating everyone to the buzzer, tallying up thousands in winnings, and then poof, I woke up and realized it was just a dream. The kicker was that the "buzzer" that I was hitting was my snooze button, I hadn't won anything, and I was late for work to boot! So goes my life...

Is the other engine running well? How hard would it be to pull the other carb off the good engine and slap it on there to see if it clears up the problem. That would possibly rule out a ruptured fuel pump diaphragm sending fuel up to the carb.

Absolutely hysterical !!!!!!!

If it has been sitting for a couple of years replace ALL of the fuel lines. The Ethanol in the gas is VERY bad news for any rubber gas lines. Make sure that you get at least a 1/2 dozen fuel filters and don't be shy about changing them. Oh and try to flush the tank REAL good. If you can, cut an access hole in the tank to gain access. Then seal it real good with a cover plate. I have done that to my alum tank and clean it out every fall.

Carbed Gen V 502 had Webers on them. If yours does can them & get a pair Of Holleys. I went thru the same problems you're having. Good thing is you'll burn less gas with the Holley Carbs and better all round performance.

Years ago when I was in high school I worked for a mower repair shop. We had a crappy old Dodge pickup as our delivery vehicle. The carb needed to be rebuilt and would regularly flood the engine. One day while trying to start it, I heard a loud bang under the hood. I jumped out, popped the hood, and saw shards of plastic all over the place. The fumes had made their way up the distributor shaft and ignited under the cap, blowing it to smithereens.