notsgnivil
Cadet
- Joined
- Dec 26, 2023
- Messages
- 7
Model J70PLSSD has sat for quite some time. With Covid lockdowns here in Australia, among other things, it has only been used about 5 times in 6 years and not started at all for at least 12 months, or possibly more.) I started it the other day and it was not too difficult to get going. I had to remove a short section of fuel hose at the primer bulb (had an obvious leak) and replace the tank connection fitting (I had a new one). Fuel line now holds pressure with no leaks, but it doesn't pump up or hold hard when connected to the motor.
With muffs on, the engine starts under choke and fast idle and then runs at idle once warm. On the water when gear selected, she won't go past 1800 rpm and if I push throttle full it stalls. To me this says fuel. BUT!!!
A bit of history. About 5 years after I bought it in as new condition, this motor developed a gradually worsening problem of intermittent power drop while running. I'd be going along flat stick, and it would suddenly die. She'd jump back to life and away I'd go all day with no further issue. It gradually worsened and I searched and searched for the problem. After going through every possible external electrical possibility, I knew I had bad spark on the bottom cylinder. I tried everything and eventually removed the flywheel only to find that before I'd bought it, someone had previously removed the flywheel and in doing so they'd screwed the flywheel puller bolts right through the wheel and into the trigger coil, which had damaged it physically. Those threaded puller holes in the flywheel go all the way through and they'd obviously used long bolts on the puller. I replaced the trigger coil and it appeared to fix it, but I only used it once or twice before it sat unused much for the last 6 years.
The point of this is that there was an electrical / spark issue, which I hope is fixed. Checking the spark the other day with a strobe timing light and a spark tester tool, indicates good spark on all 3 plugs.
So, I'm leaning towards a fuel problem. As the last person to use the boat was my son, I can't say for sure whether or not he ran the fuel out of the carbs at last use. It could have sat there with old fuel in the bowls. I've ordered 3 carb kits, but my father in law has suggested I also re-kit the VRO pump, so I've ordered a kit for that as well. He is a qualified OB mechanic, so I trust his judgement. (It was he who convinced me I had a trigger coil problem when nothing else worked.) He has a spare VRO pump in his garage that we can rebuild, which would leave mine untouched if it turns out to be just the carbys.
Is a Carburettor rebuild the most likely solution? Why does the Service Manual say that the 6 bolts that hold the Air intake Base Plate on must be replaced every time it is removed? They aren't Head Bolts.
Incidentally, while I have everything off the front end, I've got a Water Pump kit to put in as well.
With muffs on, the engine starts under choke and fast idle and then runs at idle once warm. On the water when gear selected, she won't go past 1800 rpm and if I push throttle full it stalls. To me this says fuel. BUT!!!
A bit of history. About 5 years after I bought it in as new condition, this motor developed a gradually worsening problem of intermittent power drop while running. I'd be going along flat stick, and it would suddenly die. She'd jump back to life and away I'd go all day with no further issue. It gradually worsened and I searched and searched for the problem. After going through every possible external electrical possibility, I knew I had bad spark on the bottom cylinder. I tried everything and eventually removed the flywheel only to find that before I'd bought it, someone had previously removed the flywheel and in doing so they'd screwed the flywheel puller bolts right through the wheel and into the trigger coil, which had damaged it physically. Those threaded puller holes in the flywheel go all the way through and they'd obviously used long bolts on the puller. I replaced the trigger coil and it appeared to fix it, but I only used it once or twice before it sat unused much for the last 6 years.
The point of this is that there was an electrical / spark issue, which I hope is fixed. Checking the spark the other day with a strobe timing light and a spark tester tool, indicates good spark on all 3 plugs.
So, I'm leaning towards a fuel problem. As the last person to use the boat was my son, I can't say for sure whether or not he ran the fuel out of the carbs at last use. It could have sat there with old fuel in the bowls. I've ordered 3 carb kits, but my father in law has suggested I also re-kit the VRO pump, so I've ordered a kit for that as well. He is a qualified OB mechanic, so I trust his judgement. (It was he who convinced me I had a trigger coil problem when nothing else worked.) He has a spare VRO pump in his garage that we can rebuild, which would leave mine untouched if it turns out to be just the carbys.
Is a Carburettor rebuild the most likely solution? Why does the Service Manual say that the 6 bolts that hold the Air intake Base Plate on must be replaced every time it is removed? They aren't Head Bolts.
Incidentally, while I have everything off the front end, I've got a Water Pump kit to put in as well.
