volvo penta on 40 footer boat cannot achieve full RPM?

Question

My boat's engine volvo penta TAMD 61A 306 hp can only revv up to 15000 RPM max whereas it should go up to max of 25000 RPM. What can be the probable problems and how to overcome the problem please if anybody can advise. TQ

Answer 1

Hi,
Have you done any recent work on your prop? Changed it? Or have you replaced the packing in the stern gland? Attached a safety jubilee clip to the shaft which is maybe sited too close to the stern gland? Have you conducted a recent prop re-alignment?
If you have done nothing to the prop or shaft since the RPM's were correct, then the trouble must be the engine itself.

As one guy said, I'd check the injectors first, following that you have a dubious possibility of bad fuel. I'm not convinced that bad fuel will be the cause, but it is something to check.

Best of luck,

Geoff
www.sailingunlimited.net

Answer 2

Drop prop pitch 1" for each 200RPM you want to gain. And drop 1 of the zero's in your rpm question, unless you work for a formula 1 team and borrowed a motor. This is a big heavy diesel cast iron motor. The first thing i would look at is injectors. The other obvious is bottom condition of the craft. Lots of crud will slow you down.

Answer 3

If you did not change the props before you lost all that power
there is something wrong with your engine. If you dont
know to much about engines have a qualified mechanic
check it out. That engine should tack at least 4000 Rpm

Answer 4

i'm verry perplexed at how water might are turning out to be sucked decrease back into your engine yet whilst it did, what had got here approximately is observed as hydraulic lock, that's the place your cylinder became thoroughly packed with water the two exhaust and intake valves closed, once you attempt to initiate the engine the water has no place to flow, ( air is compressed lots much less complicated than water is) the starter has alot of torque forcing the piston upwards if its packed with water the piston stops, ruining the tooth on the flywheel or starter, if it doesnt break at that factor it might desire to break the piston rods, rings, blow head gaskets, or maybe crack the block, usualy, what I even have found is that human beings will bend the rods attempting to initiate the engine, have somebody pull the plugs and eliminate the water, positioned new plugs in and run the engine, no longer noticing something appropriate away, yet as quickly as way out on the lake the rod fails and throws the rod appropriate interior the process the block, no longer good in any respect, the only way that i'm able to parent you got water on your block is the prop on your boat had to rapidly spin the oposit course this might rigidity water decrease back via your exhaust and enter your exhaust valves, yet once you have been in forward kit, due on your forward action, the prop would desire to have been loose spinning interior the comparable diriction, this confuses me, i attempted to think of of each little thing achieveable sorry i couldnt help extra

Answer 5

Problem could be prop size and pitch. Consult boat dealer for suggestions on prop change.

Answer 6

first will the engine rev to full in nuetral ?
if not forget all prop stuff and test accelerator linkages ,fuel filters etc
if revving to full then check transmission for oil etc any drive joints .... then head to prop

use the kiss principle Keep it simple stupid .
hope this helps Paul Liverpool

Answer 7

it mite just be as simple as the pitch of your prop that should be checked