volvo tamd41 not making wot

[gery w]

Hi I'm looking for a bit of advice regarding my latest purchase a 1991 Fairline corniche with 41b's The problem is I'm only able to 3200/3300rpm out of both engines and a top speed of 23knots so far I've changed all fuel filters and air filters also checked that throttle levers were hitting the stops at injector pump. whilst looking through the boat I came across an envelope from volspec with two new smoke limiter diaphrams inside and when looking at the pumps both smoke limiters appear to be adjusted differently and as I understand it this affects the fuel delivery when under load.
Any help would be greatly appreciated
Regards Gerry

 

[superheat6k]

Is the bottom clean and in particular no barnacles on the props ?

I know I loose massive revs / speed with either - mine are TAMD60C.

What were you told about max revs / speed ? If this was better previously I would put the fuel pump settings down the list of things to check.

Is the intercooler clean waterside ? If fouled the air-charge from the turbos will be less dense. Part blocked injection bends could also create a back pressure, but not so simple to check.

 

[gery w]

Hi ive also stripped both intercoolers to check and they were very clean on both the water and the air side but what I did find after a good run out last night is that there is a small amount of fuel collecting at the injector pockets although it does not appear to be from the leak off pipework or the high pressure lines.
The boat has only been in the water for two weeks so is clean
I am unable to get any information on previous performance as the boat was purchased as is were is due to bereavement.

 

[volvopaul]

Hi ive also stripped both intercoolers to check and they were very clean on both the water and the air side but what I did find after a good run out last night is that there is a small amount of fuel collecting at the injector pockets although it does not appear to be from the leak off pipework or the high pressure lines.
The boat has only been in the water for two weeks so is clean
I am unable to get any information on previous performance as the boat was purchased as is were is due to bereavement.

Your boat should have 21/22 inch props and should make 3900 rpm under load and give a healthy 30/31 knots, I've owned two of these boats so these are the figures to Aim for, as to your problem it could be that the pumps are set wrong.

Firstly you need to do a high idle governor test, when engines are warmed up to temp you need to open the throttle wide open and see a good 4100/4200 rpm on the rev counters, also make sure the alternators belts are the correct tension, do this and come back to us. No point in telling you much more at this stage, there is loads of Tamd41 posts on here if your do a search with the same problems.

 

[gery w]

Hi Paul both engines make 4300 rpm in neutral no probs also had all belts replaced and tachos calibrated.
All I know about the props is that they are four blade I will be able to check the size when the boat is lifted out for winter in a few weeks thanks.

 

[gery w]

Also forgot to say that the port engine seems to be a bit more lazy than the starboard engine and gives out some black smoke at wide open throttle

 

[tribblehunter]

Hi Gery w

What are the engine revs for each engine? Is the port one that is smoking pulling higher or lower than Sbd?

 

[gery w]

Hi both pull around 27/2800rpm on their own and come on boost when doing so?
Think the next step may be to check the prop sizes as they are four blade and from what I can gather these boats were supplied with three blade?

 

[volvopaul]

Hi both pull around 27/2800rpm on their own and come on boost when doing so?
Think the next step may be to check the prop sizes as they are four blade and from what I can gather these boats were supplied with three blade?

Early ones had there blade up to about 1990 later ones had 4 blade, I've had one of each, there faster with three blade prop, the 4,blade one I had was smoother but emitted more black smoke and it stuck on the transom after about 40 miles.

Check the gearbox ratios assuming your on volvos ms4, should be 2:63/1' any higher and that's your problem. I've seen boats with mismatched boxes before and outdrive boats too that show one engine pulling lower rpm at wot, if this is the case then that's your answer.

 

[gery w]

I've just checked the gearbox ratios and they are 2.63:1 also found a note in the owners manual (which I received from previous owner family today)quoting the props as 20x26 however I would need to lift the boat to confirm.