Volvo Penta 740 DP Lack of Power

[AJL1275]

I have just recently bought a 1994 Chris Craft Crowne 282, it had been sitting a while and I am still in the process of getting it back in good running order. I have done most of the the pre run stuff, fresh fuel, filter, oil, plugs,wires,rotor,cap etc. The boat will start and idle fine, runs good at low rpm but give it WOT and its climb stops at 3000 rpm and will not plane. Manual says 4200-4400rpm and then back down to 3500 rpm for cruise. Also, the bottom has been cleaned and painted, prop is factory issue and is straight. Any ideas out there? I'm thinking old gas has gone to varnish in the carb secondaries or? Your help is appreciated! Al

[AJL1275]

Rick,
Thanks for cheering me up.
Its a 454, 4bbl, vacuum choke, electronic ignition and you know the timing was the only thing I didnt check! but I dont think that by itself would be the problem.,
There is usually 4 aboard, 80-100 gals fuel, 25 gals water, waste-empty and always lots of beer. Trimmed down, tabs level, the prop is the original factory duoprop setup (as far as I can tell from the previous owners papers) I see you fly the Canadian flag, I'm from Newmarket Ont myself but moved to Chas SC 12 yrs ago. You can boat year round here but the downside is it costs you twice as much!

[AJL1275]

That would be great! The only problem I have is the boat is wetslipped, its 32' and real heavy to pull out even with my Ram (9600lbs) I will probably have to take it to a boatyard to get it pulled, and they know how to charge down here.
Why would the original owner change props? this is a cruiser not a bass boat. Do you really think it is the props? or should I finish set the timing and try a few other things first.

[AJL1275]

I'll set the timing, pull and rebuild the carb, change the fuel filter and see what it does. If there's no improvement it's the prop for sure. Actually the duoprop is not that expensive, it looks like about $425 locally. I appreciate your input Rick and will let you know what happens. Thanks again. Al

[Alan Wheeler]

If the engine starts OK, Runs OK, and Idles OK, it will most likely be OK.
First question, just so as we are clear and on the same page. This is the first time you have tried the boat???
So you don't know what it's performance was like in the past??
If this is first time, then suspect the prop. Just because it is factory fitted means absolutley nothing.

[AJL1275]

Wheels,
Although this is the first time I have actually run the boat there is no way the previous owner could have operated it like this and thought it was ok.The fuel consumption with the boat ploughing like that is close to 13gph, even the factory specs say 2.9gph@3500 rpm. Also, it is my understanding the boat sat unused, not run for as long as 18 mos. before I bought it.
Rick, I'm not sure about the fuel pump but I would think it's electric, checking the pressure is a good suggestion.
If the motor revs easily to 4000 in the slip, I can't see the problem being ignition/electrical related yet under load it still could be. I'm going to see if I can get a little more background on the prop issue, but when the boat was drydocked getting bottom paint the mechanic said the prop looked original and was a C series.

[Alan Wheeler]

Yeah but here's the big difference between Diesel and Petrol engines. Diesel will sound smooth but perform poorly. A petrol engine performing poorly will not sound smooth. If you have electrical issues, you will here it. As the cylinder pressure increases, it is harder for a spark to jump the gap. So the cyclinder fails to ignait. You here that in the engine note.
Water in fuel will cause the same problem. You have a ruff running engine under load.
Poor fuel will not allow a petrol to idle and is damn near impossible to start. However, I hope the fuel is new after 18mths storage anyway.
Timing doesn't just "change". OK, you do need to check maintanance. Spark plugs clean and correct gap. Gap can alter timing by the way. Electronic points solves any problems in their. Once again, if timing is off enough to affect power in that way, then it will show in starting and idle problems.
Secondaries not opening can cause top end power issues, but you wouldn't get the boat even on the plain.
Yes it is quite possible the previouse owner hasn't had this thing performing. I have seen that before. Plus they may have been operating in a very different trim and requiring a very different operation from the boat.
And lastly, how the hell do you only get 2.9gph from a 454 and full noise.
13 gph is a lot more blievable to me. Those things drink fuel. Their fuel pumps don't go click click click, they go glug glug glug.

[AJL1275]

I had a fun day, got the boat pulled to check the prop, it is correct and in good condition.
Replaced the fuel/water separator, checked fuel pump pressure-ok, cleaned fuel strainers in primaries and secondaries, changed the coil, removed the rev limiter (temporarily) put everything back together put the boat back in the water and guess what? no f*#@#$ing change!
This is killing me, I build race prepped motorcyles for a hobby so I have a pretty good understanding of motors but this thing is a nightmare! What can possibly keep it from revving up under load without any hesitation or misfiring? The only thing I can think is the secondaries are not getting sufficient vacuum to open, any ideas before I sink it for the insurance? (just kidding)

[DeepFrz]

As Rick says, or, go back and review the basics and eliminate one possibility at a time.

[AJL1275]

I like your first suggestion, I actually run a nitrous drag bike and it's very much like you described!
I've taken compression numbers way back and they were fine, about all thats left is a carb rebuild or a new one. I pulled it from the boat this afternoon and will open it maybe tomorrow, I'm out of energy today.

[AJL1275]

You know I was going to check whether the secondaries were opening today but I couldn't find anyone interested in sitting on a malfunctioning at any moment gas tank 3' down in a hole, my buddies just have no sense of adventure.
It's a Holley alright, I probably will get it rebuilt rather than new.
You guys are great, I appreciate being able to vent and get good advice.
Come on down to Charleston sometime, you'd enjoy it here.

[Bob225]

I have a '94 Crownline with the VP 740 DP. A few years back, I had sluggish top end. I bought a re-new kit and rebuilt carb. I assume you have the same Holley 4011. Found out I had a bad power value. Boat ran totally different. Before, boat never ran higher than 4200 RPM. Now closer to 4500 rpm. I have the SS F-4 props.

I know this thread was awhile ago, did you ever get it resolved?

[elyamakh]

Hi all,
I recentely bought a ROGUE CRUISERS 2300 year 1989 that needs its volvo penta 740A to be changed. I would really appreciate whether anyone could help me with this issue. Indeed I have been looking for it since a while but I can not find a used one.
Does anyone could help me ?
Thank-Regards,
hani yamak

haniyamak at hotmail dot com