triplenickel
Well-Known Member
There's more than one way to decarbon an engine.
Run outboard up to WOT sometimes?
- Thread starter Fisherman Rob
- Start date
Oly1
Well-Known Member
What's the best way you have of decarboning your engine??
Knowing what I do now from first hand experience I would pull my engines pistons after 5 seasons and clean in behind the rings by hand and then reinstall and assemble. Would cost a few bucks but far less hassle and cost than having a ring jam and break off in an intake or exhaust port and need a rebuild part way through a season.
My non marine 2strokes are liquid cooled. Actually any etec sled motor over 500cc are water cooler, we run these 2strokes WOT (8600 rpm) sometimes all day.
I could see an older 2 stroke clogging while trolling, maybe. But at WOT would debris just blow past? Newer etec marine has leading edge cooling holes and side pick vents and over heat alarms.
trophywife
Crew Member
i saw two brand new yam 350's spit a crank out on the same day!! floating valves with 0 vaccum!!
Filletandrelease
Well-Known Member
All engines at wide open throttle produce zero vacuum. If those engines were indeed floating the valves then they were over revving. Pity the poor souls who owned them. That's a hard lesson.
Pineapple Express
Well-Known Member
You sure the cranks failed? I know those F350s have had flywheel problems in the past
Pineapple Express
Well-Known Member
You sure the cranks failed? I know those F350s have had flywheel problems in the past. I doubt the ECU would let it overrev so much that the valves were floating...
flywheels and cranks on those engines....heard the crank issue before and seen it in person at a local shop. The older 50 HP Yamaha had the same broken crank problem if they were worked hard. Engines coming out of Haida Gwaii camps had failures. They put it to heavy loads pusing up big swells....without those kind of strains they were fine.
Drewski Canuck
Active Member
Just got back from Shushwap lake where a friend with a 225 HO E Tec Evinrude was WOT for about 5 minutes, and as he stepped down to take a swell, put the connecting rod through the block.
This is a 2014 E Tec which is supposed to be "super lubricated". Motor had about 10 - 12 hours on it. Yes under warranty, but the summer will be gone before the boat is running again.
If your goal is cleaning plugs and blowing carbon, 3/4 throttle for 20 minutes will do that just fine.
Drewski
This is a 2014 E Tec which is supposed to be "super lubricated". Motor had about 10 - 12 hours on it. Yes under warranty, but the summer will be gone before the boat is running again.
If your goal is cleaning plugs and blowing carbon, 3/4 throttle for 20 minutes will do that just fine.
Drewski
Pineapple Express
Well-Known Member
Ugh, that sucks! I wonder if it ran lean on decel? Can he get one of the new G2 ETECs as a replacement?
Clint r
Well-Known Member
Seems to be a lot of old two strokes still around. Pretty sure they've been run at WOT more than once in there lives. I ran my old merc 115 full tilt at least once every trip. Thing still ran great and started easily when I sold it. And it was 40 years old.
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When working up at the lodge we used to run the merc 75's and 90's at full pin everywhere they went. Then we would troll on them all day. We always traded in for brand new outboards every second season when they got up around 1500-2000 hrs on the fleet. Those engines seemed to take the WOT operation just fine with only the occasional failure. I run my verado up at 5800-6300 RPM pretty consistently when the water is flat without issue. I know my dad runs his pair of yami 250's with 1700 hours on them at 5200 RPM while cruising around. They were built to take it but they are not very economical reved right out.
yes carbon buildup is a real problem, in any engine, but there are lots of things to consider here
The key is not letting it happen, no extended idle time. If you troll with it then you will want to make sure you bring it up to normal operating temps (absolutely no need for WOT) for a good 20-30 min cruise. you usually do this just getting home from the fishing grounds.
That being said I run my old 240 sportjet at WOT for hours at a time, Always have. make sure your using premium fuel in 2 strokes as someone else mentioned pre ignition and detonation can easily happen with poor quality fuels at WOT
Fisherman Rob
Well-Known Member
Ha! that's another debate altogether as premium contains more ethanol, which is not good for older 2 strokes.
premium contains no ethonal at shell and chevron.
debates can go on forever but my old 2003 240 sportjet 2 stroke runs hard every trip on premium fuels, it doesn't even sound right with regular fuels. pings and studders bad at WOT
Fisherman Rob
Well-Known Member
And now I think about it, you are right, I've got it backwards, premium does contain less ethanol. But for some reason it's hard to track clear data down on that.
Canso
Well-Known Member
2005 merc 60/40 jet 2 stroke is a little under powered for my 16' sled, so WOT out of the hole every time, then back it up slightly till I hear a tone difference and that's it. Sometimes over an hour like that, heading to the Harrison from fort Langley and back. The only low throttle time is during warm up or getting out of a no wake zone. I was always told run your 2 stroke like you stole it.
I think they all have stickers at the pump now.
Ethanol in fuel is a huge topic on its own you right about that. But for keeping it simple sakes I usually just listen to my engines, my boat likes shell 91 or chevron 94 , so does my Harley, and sled, there's a huge difference in performance and they sound great at WOT, no pinging or ******** when running rivers or climbing mountains . my Honda quad will run the regular 86 fuel just fine and so will the wifes acura.
I'm with Canso I run my 2 strokes like there stolen 85% of the time. That's why I bought them
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