prv
Well-Known Member
My parents are out with Ariam at the moment. I've had a series of calls from them about some engine trouble, which has me baffled.
The symptom is that with the throttle full ahead (or astern) the engine will not accelerate above 500rpm. Or sometimes it will, but will take many seconds to slowly spool up to the requested speed. But sometimes it will accelerate normally. I've asked dad whether it only happens in gear or on attempting to rev in neutral as well. He thinks only in gear, but since it's intermittent can't be fully sure.
The obvious explanation is of course fuel starvation, but it's hard to see how this would be the case. Only a few weeks ago, I made an access hatch in the tank and scrubbed it out, including flushing clean fuel through all the fuel lines and replacing all the filters. So there should be no muck in the system. The boat's been used a reasonable amount since then, so any problems directly caused by the work should have come to light already. The filter bowl is reported to be crystal clear, and my dad has tried bleeding the system at the filters and at the engine, with no air being released.
Their initial thought was that something had got round the prop - as well as the low revs, my mum apparently thought the steering felt a little odd. When they initially phoned, I expected to be putting on a snorkel after work and jumping in the water - but in fact they opted to pay Saxon Wharf for a short-notice liftout! That confirms that all is well with the underwater gear, and they also tried turning the prop round by hand (saildrive in neutral, I assume) which was ok. We're assuming that my mum's comment on the steering is a red herring. The non-revving has continued after that liftout, so the idea that something was on the prop and then fell off again before lifting doesn't fly.
I know that prop size can have an influence on this sort of thing, but that obviously doesn't apply since the problem has only recently appeared, and is intermittent. And the prop is Volvo's own one specified for the engine and drive anyway.
Throttle controls are all in good order and moving the levers on engine and gearbox.
Engine is fairly new, saildrive was brand new last winter (long story, the engine had previously been mated to an older drive).
Any ideas? All I can think of now is to get someone to have a look at the injector pump/governor assembly.
Pete
The symptom is that with the throttle full ahead (or astern) the engine will not accelerate above 500rpm. Or sometimes it will, but will take many seconds to slowly spool up to the requested speed. But sometimes it will accelerate normally. I've asked dad whether it only happens in gear or on attempting to rev in neutral as well. He thinks only in gear, but since it's intermittent can't be fully sure.
The obvious explanation is of course fuel starvation, but it's hard to see how this would be the case. Only a few weeks ago, I made an access hatch in the tank and scrubbed it out, including flushing clean fuel through all the fuel lines and replacing all the filters. So there should be no muck in the system. The boat's been used a reasonable amount since then, so any problems directly caused by the work should have come to light already. The filter bowl is reported to be crystal clear, and my dad has tried bleeding the system at the filters and at the engine, with no air being released.
Their initial thought was that something had got round the prop - as well as the low revs, my mum apparently thought the steering felt a little odd. When they initially phoned, I expected to be putting on a snorkel after work and jumping in the water - but in fact they opted to pay Saxon Wharf for a short-notice liftout! That confirms that all is well with the underwater gear, and they also tried turning the prop round by hand (saildrive in neutral, I assume) which was ok. We're assuming that my mum's comment on the steering is a red herring. The non-revving has continued after that liftout, so the idea that something was on the prop and then fell off again before lifting doesn't fly.
I know that prop size can have an influence on this sort of thing, but that obviously doesn't apply since the problem has only recently appeared, and is intermittent. And the prop is Volvo's own one specified for the engine and drive anyway.
Throttle controls are all in good order and moving the levers on engine and gearbox.
Engine is fairly new, saildrive was brand new last winter (long story, the engine had previously been mated to an older drive).
Any ideas? All I can think of now is to get someone to have a look at the injector pump/governor assembly.
Pete
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