Denis O
Member
Firstly spec. Chaparral 180SS with 3.0 Litre Mercruiser inboard with 21 hours with carb, full tank of gas and all fluids 100%
Was out today for the first time in a couple of weeks. She fired up on the slipway no problem and off we went. Got about 6 miles and the engine spluttered a little. We were running at around 3500 revs. In hinsight it felt like it was holding back a little from the start. The splutter was minor, and it had done it before a few times in the past at higher rev levels so I didn't really worry.
It then lost all power, shuddered a little and I pulled the throttle back to neutral. It dropped to tickover and was fine. The rear passengers said they could smell petrol and the engine had a loud tick. The tick went off after about 15 seconds and we decided to head back to the slipway.
I was pretty sure this was fuel starvation of some sort so we ran at about 1500 revs for a while and no real problem apart from how slow we were going. Pushed it up to 3000 revs to get her on the plane and was moving along at about 25 mph and again we lost all power. Throttled back to neutral and she ticked over again without problems. The ticking was back, no louder, and it went off after 15 seconds. Tried a few times at 3000 rpm and she would run for a few minutes then die. If I didn't get the throttle back to neutral quick enough she would cut out completely but start easily straight away.
Next I tried a little Italian tune up and went for a full bore start and to WOT. It got up on the plane, ran for about 10 seconds at 4000+ revs and then lost all power again. We managed to get bak to the slipway at low revs and the boat is now back at home and awaiting some TLC.
Does my fuel starvation diagnosis sound feasible? If so how is the fuel system made up. I can see where the fuel comes out of the tank via a pipe in the rear left corner (looking from inside the boat). It then goes off to what looks like a glass bowl which I suspect is the filter or mechanical pump and then converts to a plastic clear tube that goes to the carb. Is there an electric pump in the tank. With the exit at the top of the tank I'm guessing it needs something to push it up there. Is the ticking relevant. Can't remember if it was there before when all was good.
If it's not fuel starvation are there any other possibilities to sort it out.
Cheers guys.
Was out today for the first time in a couple of weeks. She fired up on the slipway no problem and off we went. Got about 6 miles and the engine spluttered a little. We were running at around 3500 revs. In hinsight it felt like it was holding back a little from the start. The splutter was minor, and it had done it before a few times in the past at higher rev levels so I didn't really worry.
It then lost all power, shuddered a little and I pulled the throttle back to neutral. It dropped to tickover and was fine. The rear passengers said they could smell petrol and the engine had a loud tick. The tick went off after about 15 seconds and we decided to head back to the slipway.
I was pretty sure this was fuel starvation of some sort so we ran at about 1500 revs for a while and no real problem apart from how slow we were going. Pushed it up to 3000 revs to get her on the plane and was moving along at about 25 mph and again we lost all power. Throttled back to neutral and she ticked over again without problems. The ticking was back, no louder, and it went off after 15 seconds. Tried a few times at 3000 rpm and she would run for a few minutes then die. If I didn't get the throttle back to neutral quick enough she would cut out completely but start easily straight away.
Next I tried a little Italian tune up and went for a full bore start and to WOT. It got up on the plane, ran for about 10 seconds at 4000+ revs and then lost all power again. We managed to get bak to the slipway at low revs and the boat is now back at home and awaiting some TLC.
Does my fuel starvation diagnosis sound feasible? If so how is the fuel system made up. I can see where the fuel comes out of the tank via a pipe in the rear left corner (looking from inside the boat). It then goes off to what looks like a glass bowl which I suspect is the filter or mechanical pump and then converts to a plastic clear tube that goes to the carb. Is there an electric pump in the tank. With the exit at the top of the tank I'm guessing it needs something to push it up there. Is the ticking relevant. Can't remember if it was there before when all was good.
If it's not fuel starvation are there any other possibilities to sort it out.
Cheers guys.