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ran my 787 engine with no oil for 30 minutes and no ill effects?

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drake1

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i was out on the lake with a seadoo with a 787 engine that i just got well the fuel gauge doesn't work like every other seadoo and the little red light was on where it said fuel/oil warn. i thought it was just the low fuel from the bad sending unit but turns out that the oil line popped off and drained the entire oil tank into the hull. i ran it for maybe 30 minutes at low speed since i was pulling a kid in a tube never got over 4000 rpm. i thought this would destroy the engine but not having oil usually takes out the piston rings first so i did a compression test and i am still getting 150 psi in both pistons and engine runs great. Any one else ever have this happen? the engine is also a sbt rebuild..not sure how it could function that long without taking out a ring or at least losing some compression
jeff
 
I wouldn't say you're out of the woods just yet. The bearings, rotary gear oil pump piston rings etc all rely on that oil for lubrication. It might run for another hour or it might run for another 100hrs you just won't know with out tearing into it. At least pull the head and look for piston scoring or just use as is and if it lets go at least it would be expected. Is it still under warranty?
 
Yeah and if you run premix then your rotary gear and everything else that is also lubed with oil only (not gas and oil) is running dry. I've been told over and over that the stock oil pump will easily outlast the ski and the only weak points are the lines cracking from age and the owner ignoring the flashing red idiot light (if so equipped).
 
HighBeam said:
Yeah and if you run premix then your rotary gear and everything else that is also lubed with oil only (not gas and oil) is running dry. I've been told over and over that the stock oil pump will easily outlast the ski and the only weak points are the lines cracking from age and the owner ignoring the flashing red idiot light (if so equipped).
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This is HIGHLY inaccurate. When you premix you keep a loop of oil or keep the oil tank connected to the rotary shaft. There is nothing that goes unlubed when you premix, so please dont put stuff out there if you dont know what you are talking about. The only time premix fails is when you mix the incorrect ratio or when you forget to put oil in the tank, and if you cant figure that out, then it is user error.
 
It's not that I love the premix gas...actually I hate modifying something other than stock...unless I go full out on modifications...I have a friend that has probably 200 ski's at any given time...lives in the middle of nowhere and has more business than a dealership in the middle of a big city. He has seen probably every worse case scenario when it comes to a jet ski. His first suggestion to all of his customers with non fuel injected engines is to go premix. He has a waveraider 701 that he installed an hour meter on and it has well over 800 hours on it..the thing looks like a piece of s**t but it cranks first 3 sec. no choke cold and had used premix gas for the term of the engine. He has had the ski for over 10 years same engine.
 
HighBeam said:
Yeah and if you run premix then your rotary gear and everything else that is also lubed with oil only (not gas and oil) is running dry. I've been told over and over that the stock oil pump will easily outlast the ski and the only weak points are the lines cracking from age and the owner ignoring the flashing red idiot light (if so equipped).
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incorrect...
if you run premix correctly, the rotary gear is not in any danger at all, i just has to be looped.

if you run premix all ghetto'd up, then ya, it won't work.

however, the one thing you did say that is correct, the stock pump is very stable and generally the ski makes it to the dump long before the oil pump fails. IMO, if you have a ski with a functioning oil pump, just change out the lines and keep running it, no real good reason to premix except for maybe high performance, high rpm users, i run my ski very hard at times, and I premix really only because I started out riding on yami's (weak oil pump) and got into the habit of premixing so now I just keep it that way on all my personal ski's, i've never actually owned a "stock" seadoo, all of my ski's have had mod's to some degree.
 
yeah it usually takes a little while for it to actually let go....i had a snowmobile one time that i ran for about an hour with no oil...it ran like a dream till it quit on me at about 80 miles an hour in the dark down the side of the road ...talk about scary...but i freed it up and wrode it for a few more days then it completly gave out......
 
ya, engine's can be weird, I had an old xp that had a lean seize during a carb tune, stuck the piston, let it cool off on the water, adjusted the carbs, and it rode fine for 100+ hours before It finally crapped out.
 
Premix is all good and so is the oil pump. Problem with premix with two stroke engines is when a carb fowls it leaves a cylinder with out fuel and OIL. Unlike the oil pump that keeps oiling during a lean condition. See it all the time in outboards that are two cycle the people take the oil pumps off to avoid a failure and usually cause there own by not having optimal carb conditions. To each his own do as you please but pump is better no human error.
 
Tsef said:
Premix is all good and so is the oil pump. Problem with premix with two stroke engines is when a carb fowls it leaves a cylinder with out fuel and OIL. Unlike the oil pump that keeps oiling during a lean condition. See it all the time in outboards that are two cycle the people take the oil pumps off to avoid a failure and usually cause there own by not having optimal carb conditions. To each his own do as you please but pump is better no human error.
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I have heard of spark plugs "fouling" but not carbs, please explain. 2 stroke engines have been used for years and years without oil pumps...lawn mowers, weedeaters, chainsaws. I bet a thousand bucks my 1970's two stroke lawnboy wouldn't still be running if we had to service the "oil pump" every so often. Sorry, but I am tired of the Premix vs Oil Pump conversation. Im sorry but I see WAY more people on her complaining about their oil pump having problems/ being serviced/ replacing parts, than I have seen people complaining because they forgot to put oil in there gasoline.
 
I think you are all ignoring the possibility that he ran for 30 minutes with no oil in the tank, but could have not run all the oil out of the hose. If you check the line that goes to the oil pump, you might be surprised to find that 30 minutes at part throttle didn't use all of that oil up.
 
Strizzo said:
I think you are all ignoring the possibility that he ran for 30 minutes with no oil in the tank, but could have not run all the oil out of the hose. If you check the line that goes to the oil pump, you might be surprised to find that 30 minutes at part throttle didn't use all of that oil up.
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good point!!!!!
 
Dr Honda said:
Why is this a "Good reason to run pre-mix?" If someone doesn't add oil... it has NOTHING to do with the injection pump !!
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In the very first post of this thread Drake1 said "i thought it was just the low fuel from the bad sending unit but turns out that the oil line popped off and drained the entire oil tank into the hull".
 
I have heard of spark plugs "fouling" but not carbs, please explain. 2 stroke engines have been used for years and years without oil pumps...lawn mowers, weedeaters, chainsaws. I bet a thousand bucks my 1970's two stroke lawnboy wouldn't still be running if we had to service the "oil pump" every so often. Sorry, but I am tired of the Premix vs Oil Pump conversation. Im sorry but I see WAY more people on her complaining about their oil pump having problems/ being serviced/ replacing parts, than I have seen people complaining because they forgot to put oil in there gasoline.



Maybe I should choose my wording differently for the people who read into wording too much. Not here to argue th point which is better just stating fom being a outboard mechanic for 16yrs it has shown itself many time that premix is user discretion. But more out lares motors fail"2 stroke" fail alot more Often because user blocked of pump and premixed their own fuel. By fowling i meant that a carb picks up dirt or whatever it may be and clogs low or high speed jet now no fuel or oil. Not here to argue the point I'm just stating fact from 16yrs experience. Do whatever makes you feel best. I like the pump I use less oil than premix and all it takes is a few to service the pump. Premix is fine as long as you service your carbs. Once again only stating my opinion from what has been seen by my two eyes.
 
Yeah I understand that it uses less oil and is more efficient, but you are gunna pick up "dirt or whatever" with or without premixing your gass. The oil in the gas tank isn't like a magnet for picking up dirt and sucking it into your carbs. Alot of general users wouldnt ever think to have to replace oil lines, because why should they ever fail? And in all honestly, i dont know why they should fail. Does anyone ever have to replace oil or gas lines on their car because they are broken or deteriorating? No. So to the casual PWC user, why should you ever have to replace them in a Seadoo?
 
That's what makes seadoo a part of all of us who work on them. We become one with the machines maintaining them. But when they run correct not too much is better.

About missing the oil for thirty minutes if it still runs, run it til it dies it may not happen for a long time why worry it seams to be bullet proof. Fix the oil line and enjoy!! Do the Doo!!!
 
CReynoldsMIZ said:
Yeah I understand that it uses less oil and is more efficient, but you are gunna pick up "dirt or whatever" with or without premixing your gass. The oil in the gas tank isn't like a magnet for picking up dirt and sucking it into your carbs. Alot of general users wouldnt ever think to have to replace oil lines, because why should they ever fail? And in all honestly, i dont know why they should fail. Does anyone ever have to replace oil or gas lines on their car because they are broken or deteriorating? No. So to the casual PWC user, why should you ever have to replace them in a Seadoo?
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I just had a 2010 jeep wrangler come in that caught on fire becasue the gas line got brittle and broke.....just sayin:coolgleam:
 
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