Neither engine will rev beyond 2,000 under load - and it's not fuel

H

h4nym

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Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Hi guys

Any ideas on this one... first time out beyond Wandsworth for a few years, so had the chance to open her up a little... but weird - engines (2 x Volvo TAMD 40Bs 165hp ) will happily rev to 4,500 in neutral, but won't rev beyond about 2000 under load.

I don't think it's fuel-related, simply because with the throttles fully open, there's lots of black smoke about which tells me that the fuel is being pumped in, but remaining unburnt...

Anyone got any ideas? Compression?

H
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Frist thought is what about prop dimensions ? Sounds as if your are over propped or weeded up ?
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Check the turbos spin easily, whip the air filters off and spin them by hand.
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Sounds like its not getting over the hump onto the plane, did you try to trim her with the outdrive controls? apply bow down full trim once over the hump the revs will rise.

I am assuming fuel and air filters are clean.

Chill
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

They just need 'working' a bit. Keep running up and down the rev range and they will start to loosen up. After a few runs at decent revs they should be back to normal.
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Really far fetched answer but one I have seen in the past. How clean is your bottom? If your hull is really bad it will give the same effect as being over-propped.
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Thanks for all your suggestions, folks...

I think the two with legs (sorry!) are the trim and the air filters... I'll take a look. Unburnt fuel suggests that they could be "wheezing" with inadequate air. I'm not sure I can recall changing the filters since - oh god I'm embarrassed now - well let's just say "this century"!

She's too old to have turbos sadly, and we've only just replaced the props while she was ot of the water last month being antifouled.

The air filter thing seems to be the most likely culprit if it isn't trim and train... ie just keep nudging up and down until she learns to open up again.

I'll have a look at the air filters over the weekend. In the meantime, I'd be really grateful for you to keep the suggestions coming.

H
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Excuse me for asking but TAMD 40B's without turbos????

I thought TAMD stood for

Turbocharged
Aftercooled
Marine
Diesel

Neil
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

You live and learn, Moody! I had no idea that that's what the TAMD stood for that!

Must be said that there don't seem to be any appendages that look or sound like a turbo - let alone having experienced any commensurate performance!

You have me puzzled now! I'm pretty certain that they're TAMD 40B's... but I'm equally certain that they're not turbo's. Hmmm.... I'll take some photos over the weekend and throw myself at the mercy of my superiors!
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

I would be very surprised if there were no turbos attached to the green monsters.

I have seen on this on other models like yours and indeed Sunfurys and 27's.

Take everything off the boat, I mean, TV's, bedding, shoes, clothes, useless items youthoguhts woudl be a "good idea" and I bet you you could fill a small van...add to this a build up of river slime which take no time at all even whit decent anti foul and a lack of service this century and it all starts to make sense.
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fue

Not me Guv! They would not fit on a Sea Panther... /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

[ QUOTE ]
Take everything off the boat, I mean, TV's, bedding, shoes, clothes, useless items youthoguhts woudl be a "good idea" and I bet you you could fill a small van...

[/ QUOTE ]

Did that a few years ago - just to create capacity for beer! /forums/images/graemlins/laugh.gif

Nah - I'll definately look for some turbos... certainly not aware of any turbo-like performance for several years! Was out on the river in London last night - 2000 revs with 11 on board (and lots of beer!) was definately producing unburnt out the back. I'll have a look and report back.

H
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

I undertsood:
light grey/blue smoke- unburnt fuel
Grey smoke - burnt oil
black smoke - over fuelling/miss burnt fuel
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Have the same problem myself, have been recommended by the club "oily rag" to crack open the bleed screw on the injection pump when engine running as most probably a bit of air stuck in the pump.

Will let you know what happens when I get around to it....
 
Re: Neither engine will rev beyond 2,000 under load - and it\'s not fuel

Thanks guys... I did look under the lid on Sunday and there was a suspiciously turbo-resembling appendage on the end of the air intake. But it was at the other end of the engine, so I didn't look too hard!

So - in order... this is what I plan to do:

1. Ensure that the air filters are good
2. I'll look at the bleed screw on the injection pump; and
3. I'll try and marry off my daughter to a rich Russian in anticipation of his pity and extravagant gift of replacement turbos:

Hello Sir - how can I help
Oh hi there - I need a couple of reconditioned turbos
Ker-ching! Very good sir... for what engine?
Erm... Volvo
Ker-ching!
Erm... Volvo Penta
"Wifey - dust off those retirement plans"

:-(
 
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