I put another gallon of oil in the oil tank last night. The oil warning light no longer lights up red. Still no joy.
I'm fresh out of ideas & have to pack the boat up & pull it home in about 6 hours.
Anyone with ideas, please share them so i can try while it is in the water.
-Series of events before it died:
engine rebuilt by SES. Has run about 2 hours prior to this trip, but on the old carbs, was surging and only wanted to run well when the high speed carb jets kicked in
Fresh rebuild of both carbs this week. low speed needles @ 2 turns out, pop-off at 32psi, high speed needles at 2 turns out
fuel selector valve sprayed out with carb cleaner & blown out with compressed air
fuel baffle removed, screen cleaned
inline fuel filter installed between spin-on filter and carb inlet
new spin-on filter installed
new oil injection filter installed (this is where I forgot to tighten the bleeder screw... it was only hand tight and fell out)
it ran on the gas that was in the boat when i bought it... gas was from august and was stabil treated in Dec. however, i syphoned 15 gallons out and replaced with fresh 92 octane before the last outing. So, roughly 30% old, 70% new.
pre-mixed at 50:1 or stronger (more oil)
test fired on the trailer... took a few tries to get the fuel system primed, but once the gas was flowing it fired and ran just above idle for 10 sec before i shut it off.
the next day at the lake, after probably 10 sec of cranking it started. Ran fine as long as i kept it just above idle. had to let it warm up for a few minutes before i could bring it to idle to change from neutral to fwd or reverse... but within 5 minutes I was able to move the boat about 500 yards through the no wake area from the boat ramp to my dock. idle speed was around 1k and it would sometimes die at idle, but if i kept it at 1,100, it ran great. Shut it down for 15 min before going out for a ride outside the no wake area.
First time outside the no wake area it did good at low speeds, but wouldn't get to 4k rpm, even at full throttle.
At the dock, adjusted idle speed screw to get 1,100 rpm at 0 throttle. turned in the low speed screws to 1.5 turns out, turned in the high speed screw to 1/4 turn out.
2nd time outside the no wake area it bogged a bit for the first 5 seconds or so of 1/2 throttle, then picked up rpm and got us on plane. Ran around for 5 min or so going up and down from idle to 85% throttle. then going from idle up to get back on plane it felt like it was bogging a bit for a couple of seconds, then ran strong for 3 seconds, then started losing power (throttle position constant at around 75% through this) and died. hasn't started since.
Bilge had a layer of oil floating on the inch or two of water in the bottom. Got towed in.
Checked the fuses in the MPEM while being towed. All fuses looked good.
Once at the dock, found that the oil pump bleeder screw had wiggled loose. Couldn't find the screw, but had a spare oil pump assembly with me, so installed the spare screw. (found the original screw in the bilge later)
Changed to fresh plugs after a few attempts to restart... the "old" ones (less than an hours use) were damp, but looked fine.
Noticed that the clear fuel filter between the spin-on and the carbs had only 1/2 cm of gas in it. i remember looking at it in my garage after the test fire and it was over 1/2 full, and even totally full at one point. As i cranked it, the inline filter emptied and did not refill. So i assumed it was a fuel starvation problem.
I had been warned that the fuel selector could fail, while still passing compressed air, and that the o-ring in the spin-on filter could leak. so, I Removed the fuel line from the "on" port on the fuel baffle.
Removed the output fuel line from the spin-on filter and connected it to the "on" port on the fuel baffle (bypassing the entire fuel selector and spin-on filter)
Now the inline fuel filter sits at about 1/4 to 1/3 full and doesn't completely empty when cranking.
I've since pulled the spark arrestor and see that after cranking for 15-20 seconds, there is a pool of gas/oil in the low point of the spark arrestor housing. When i cranked it with the spark arrestor out, it sprayed a mist of gas/oil in the engine bay. So, I think fuel is being delivered. Not sure why it isn't being sucked in the engine though.
I tried shooting a quick blast of "starting fluid" in the spark arrestor both before and during cranking. It did not fire.
so, at this point I'm thinking it is acting like it isn't getting a spark. so I pulled the plugs and checked for spark again and both still spark.
Held a paper towel over the open plug holes while i cranked it. PTO side spit out some gas, mag side didn't. I'll try this again. Even if only one cylinder were getting fuel, i would expect the other one to fire, at least occassionally. i'm not getting any firing right now.
while typing this I see that jhjesse suggested checking the fuel pump diaphram. I may do this shortly, although the fact that the starting fluid didn't make it fire really makes me think this isn't a fuel starvation issue after all.
To say that i'm baffled really doesn't do this justice.
I keep thinking that there must be some sort of safety circuit... like something triggered by the oil tank level sender showing the level dropping so quickly. Or something like the head temp gauge that causes it to not run.... but any option i can think of, i would expect that the safety circuit would cut the spark. So, since i see the spark, I'm thinking that it isn't a safety circuit cut-out.
With the oil feed bleeder out i think the obvious suspect is that the cylinders are fried and I don't have compression. I haven't wanted to consider this since I an running a strong pre-mix ... but I guess I should see if anyone here at the marina has a compression gauge I can use.
If it wasn't obvious before, I am not a 2 stroke or Rotax expert. I'm going to keep reading the shop and operator manuals this morning in hopes of better understanding all of the systems that could be at play here.
uke:
