Need a little help over here;
Here's what it does; it runs great. Unless you put the throttle to the bulkhead and leave it there. You may run 3 or 4 miles at 5250 RPM humming along . . . . then you'll feel it. It'll feel like a miss then the engine winds down and boat drops in the water. If you de-throttle within a second, you may save it at idle. If you leave the throttle more than a little open the engine will die. It will restart, though it may require reprime or choke. It ran a tad rough for a while after that happened, until I replaced the reeds. But the engine won't stall unless you go to WOT. If you go to 7/8 throttle you can run for miles and miles and not have the problem. It only seems to happen at WOT.
Here's what I've done (one at a time and with increasing frustration each time the problem didn't go away); New plugs (cured the occasional miss I had been having), fuel filter primer bulb and reeds. I rebuilt the fuel pump (twice) and replaced the factory reeds with dual stage carbon fiber. I ohm'd the coils; all the same, all good, strong spark in all 4 holes.
I adjusted carbs and idle per the manual (mostly because it was necessary after replacing the reeds). (separate issue; The reeds needed replaced when in the middle of trying to fix the 'drops in the water' problem the engine started to idle really rough, would stall when shifted into gear or throttled up. It lost rpm and I noticed gas blow-back through the lower carb. On inspection; 1/2 of a reed had shattered and another had just a small piece of the corner missing. All good now though.)
Put it all back together, adjusted carbs (idle mixture) and idle speed with the boat idling in gear in the water. It runs and sounds great.
I was really disappointed again when after I replaced the reeds and took it out, full on trucking across the lake when . . . down in the water it went. But it still restarts right away and now it runs great even after it stalls.
I've checked for a fuel leak or a blocked vent line. I assume if its not leaking fuel its also not sucking air. You can definitely get a mouth full of fuel up from the tank without working too hard, even with the gas cap closed, so I don't think its vent or pickup related. If I pump up the bulb there will be pressure through the quick coupler, pump and filter an hour later. Not so much if I run the engine, but the bulb stays full. (One of the new bulbs I put on would suck flat. Bad out of the factory or just a cheap bulb maybe.) There are no fuel leaks between the pump and the carbs. that I can identify.
When I tilt the motor up fuel will drip out of the upper carb. (When not running, I haven't .) I think its the fuel in the bowl draining out. Somebody told me that's normal. Not sure I believe it. Could it be a sticking float problem? Doesn't seem right to me.
What remains; compression test (will do next weekend, but seems irrelevant to a boat that planes out almost as quick as the throttle is pushed forward and it runs as fast as it has ever gone), pull the bowls on carbs and check for sticking floats. This doesn't seem too likely to cause the boat to drop in the water but I will check it. That the new (clear) fuel filter stays full when running at WOT. I need to let it die completely, pull the cowling and look. So far I always try to stop it from dying. It is possible that I screwed up the rebuild on the fuel pump, but it sure fills the filter in a hurry. I also haven't checked vacuum. But again the pump seems to run pretty good and I don't have a vacuum gauge. Might have to get one.
Also, somebody may have screwed with the timing a bit while all of this was going on, calling it the governor. I don't have a timing light so I can't re-adjust it. But again, the engine runs great except at WOT.
I believe the problem is fuel related because I can keep it from dying by quickly cutting the throttle and all the coils ohm out the same/good.
Also; ran it to within about a half gallon of empty twice and put in fresh non-ethanol fuel and premium 2 cycle oil. I'm pretty sure its not a water in the fuel or stale fuel problem.
If anybody out there has experienced this orcan tell me what the problem is I would be very appreciative.
Sincerely,
Cooter
Here's what it does; it runs great. Unless you put the throttle to the bulkhead and leave it there. You may run 3 or 4 miles at 5250 RPM humming along . . . . then you'll feel it. It'll feel like a miss then the engine winds down and boat drops in the water. If you de-throttle within a second, you may save it at idle. If you leave the throttle more than a little open the engine will die. It will restart, though it may require reprime or choke. It ran a tad rough for a while after that happened, until I replaced the reeds. But the engine won't stall unless you go to WOT. If you go to 7/8 throttle you can run for miles and miles and not have the problem. It only seems to happen at WOT.
Here's what I've done (one at a time and with increasing frustration each time the problem didn't go away); New plugs (cured the occasional miss I had been having), fuel filter primer bulb and reeds. I rebuilt the fuel pump (twice) and replaced the factory reeds with dual stage carbon fiber. I ohm'd the coils; all the same, all good, strong spark in all 4 holes.
I adjusted carbs and idle per the manual (mostly because it was necessary after replacing the reeds). (separate issue; The reeds needed replaced when in the middle of trying to fix the 'drops in the water' problem the engine started to idle really rough, would stall when shifted into gear or throttled up. It lost rpm and I noticed gas blow-back through the lower carb. On inspection; 1/2 of a reed had shattered and another had just a small piece of the corner missing. All good now though.)
Put it all back together, adjusted carbs (idle mixture) and idle speed with the boat idling in gear in the water. It runs and sounds great.
I was really disappointed again when after I replaced the reeds and took it out, full on trucking across the lake when . . . down in the water it went. But it still restarts right away and now it runs great even after it stalls.
I've checked for a fuel leak or a blocked vent line. I assume if its not leaking fuel its also not sucking air. You can definitely get a mouth full of fuel up from the tank without working too hard, even with the gas cap closed, so I don't think its vent or pickup related. If I pump up the bulb there will be pressure through the quick coupler, pump and filter an hour later. Not so much if I run the engine, but the bulb stays full. (One of the new bulbs I put on would suck flat. Bad out of the factory or just a cheap bulb maybe.) There are no fuel leaks between the pump and the carbs. that I can identify.
When I tilt the motor up fuel will drip out of the upper carb. (When not running, I haven't .) I think its the fuel in the bowl draining out. Somebody told me that's normal. Not sure I believe it. Could it be a sticking float problem? Doesn't seem right to me.
What remains; compression test (will do next weekend, but seems irrelevant to a boat that planes out almost as quick as the throttle is pushed forward and it runs as fast as it has ever gone), pull the bowls on carbs and check for sticking floats. This doesn't seem too likely to cause the boat to drop in the water but I will check it. That the new (clear) fuel filter stays full when running at WOT. I need to let it die completely, pull the cowling and look. So far I always try to stop it from dying. It is possible that I screwed up the rebuild on the fuel pump, but it sure fills the filter in a hurry. I also haven't checked vacuum. But again the pump seems to run pretty good and I don't have a vacuum gauge. Might have to get one.
Also, somebody may have screwed with the timing a bit while all of this was going on, calling it the governor. I don't have a timing light so I can't re-adjust it. But again, the engine runs great except at WOT.
I believe the problem is fuel related because I can keep it from dying by quickly cutting the throttle and all the coils ohm out the same/good.
Also; ran it to within about a half gallon of empty twice and put in fresh non-ethanol fuel and premium 2 cycle oil. I'm pretty sure its not a water in the fuel or stale fuel problem.
If anybody out there has experienced this orcan tell me what the problem is I would be very appreciative.
Sincerely,
Cooter
