SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: metalmechanic on April 12, 2014, 10:23:53 PM
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hoping one of you guys has an idea, my 73 Tahiti with a 455 has steam out the exhaust both sides, first only under load, now at 1000 rpm and up no load, oil is clean, has to be the exhaust but I can't see both manifolds failing at the same time. what do you think?
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hoping one of you guys has an idea, my 73 Tahiti with a 455 has steam out the exhaust both sides, first only under load, now at 1000 rpm and up no load, oil is clean, has to be the exhaust but I can't see both manifolds failing at the same time. what do you think?
You do not state exactly what exhaust system you have.. Logs with OT pipes, Logs with through transom snails, later style center riser?
Steam out of the exhaust is totally normal in 99 out of 100 cases.. I freak when I don't see it... ;)
GT
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they are logs with through transom snails and the steam is not what is considered normal. its very heavy smoke-steam under load and steady smoke-steam over 1000rpm
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not enough water going thru the system? try opening the valve from the jet more maybe???
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What does your water temperature gauge tell you?
Sounds normal, if you were driving the boat on a very cold, or very humid day, the steam amounts will increase.
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they are logs with through transom snails and the steam is not what is considered normal. its very heavy smoke-steam under load and steady smoke-steam over 1000rpm
No offense bro but your post count is "2" and you are a noob. How would you know what's normal and what's not???? Steam at certain times might seem like smoke. Don't be fooled.
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i even get steam from time to time on my exhaust in the right wind/temp. the worst is when its blowing over the back and gets everyone wet... and i have a shitton of water going thru it.
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You're fine. As long as you can akways grab the logs and they're cool to the touch. I'd run 3500rpm upriver boat never went over 140*
from my phone
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If logs even get too warm. .. something is restricted.
from my phone
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Thanks for the feedback, water temp runs about 150 on the lake. I'll play with the water adjustment before I pull a manifold and psi check it to see if it's cracked, or restricted. my prob. is I can't see it being both manifolds, no misfire, no water in oil, good power. but if you load it up, smokes like a freight train. quick history, boat is stock bought it from orig. owner last year. ran, runs great. problem started end of last season, did some work on it, thought I had fixed it. nope, isolated it to steam last weekend. thanks again.
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Logs get clogged easy. I run in pretty shallow water and always suck sand and pebbles. I installed shut off valves on block so i can drain water and debris every trip. I always remove the hoses that go from thermostat los and run water backwards the sand and crap will pour out the back. My log system never created pressure like ot headers do.
from my phone
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its very heavy smoke-steam under load and steady smoke-steam over 1000rpm
Could you please describe the “smoke”? Is it black (fuel) or blue (oil)? Could the smoke be from a mechanical problem that is not necessarily related to the water in the exhaust?
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Good point....my beer goggles keep me tracking in one direction. Check all the possible factors first!
from my phone
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the smoke is white, not blue not black, because it was from both manifolds I convinced myself it had to be air- fuel related the carb. was original and temperamental I had a new one I'd been saving so I installed it resealed the intake manifold, ran it and thought I had it, put it away. ran it last weekend for an oil change white smoke again, heavy. let it cool a bit restart ran 5-10 seconds with no water, no smoke, very clean. it's steam
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Are we talking smoke-screen amounts of steam? How do the spark plugs look? If they look new, you have a little water-injection action going on with some water sneaking back in through the exhaust valve.
Honestly, I have moved beyond logs a long time ago and never looked back. I run through-transom headers with every drop of water that goes through the engine dumping into the headers. There is a little steam while underway and I don’t notice any steam while idling.
As far as smoke, I run mechanical injection that is tuned a bit fat at idle. I don’t see any smoke at idle, but its presence is apparent from the sooting on the transom and swim steps. While underway, I don’t see clouds of billowing smoke pissing off the environmentalists, but there is some caught in the turbulent air trapped between the transom and wake. Though I don’t see huge clouds of smoke, I do know that it is tuned a bit on the rich side to prevent lean-out.
Idling 5-10 seconds with no load or even a quick rap of the throttle may not be enough to get a mechanical problem to rear its ugly head. While idling on a trailer or in a marina, you will probably never see any issue until you get out on open water and under load. It is hard to diagnose online with limited information. I don’t really see too much water through the exhaust being the cause of too much steam. I have seen water pouring out of the exhaust in situations like mine where all water exits the exhaust, just not in the form of excessive steam. I believe that your exhaust dumps under water until speed increases. Again, I don’t see a bunch of steam/smoke here as the water will actually filter out particulates and condense steam. Your old carb was “temperamental”, if it went lean under load, it could have overheated the logs and caused cracks in both sides at the same time. I don’t see cracks in the logs causing excessive steam, especially if you are not getting reversion.
The reason I ask about a mechanical problem is because once-upon-a-time, my baby’s momma bought (against my wishes) a ’92 Lumina. Under normal driving conditions, it ran great. During WOT acceleration (passing) it would blow a huge smoke-screen. I was so over that car by then that I didn’t even want to try to look into the cause, but I think that high-RPM caused the rings to flutter and lose seal and oil control. Shortly after, sis and bro-in-law blew it up and I didn’t have to look at that POS any longer.
I am sorry brotherman, if it is not a mechanical issue, I am stumped.
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thanks Flusher I appreciate the input, I'm going to start on it before work tomorrow, as far as the environmentalists, don't kid yourself if you aint pulling a kayak up to the lake behind a 3 cylinder hybrid your no true friend of the frogs. they hate all of us.