rev limits of volvo 4.3

[rob935]

hi guys i have a 92 430 a volvo engine which has yet to see any action yet due to a few early problems, i have put two new manifolds new starter and water pump but have noticed that it seems to rev out at around 3500 just wondering if this is normal as my previous experiences have been with 3L mercruisers any thoughts ??

 

[Bondo]

Re: rev limits of volvo 4.3

You Should be seeing 4400/4800rpms, WOT.......

 

[rob935]

Re: rev limits of volvo 4.3

thanks bondo , had cracked manifold when i ran it last weekend would this affect the performance, the 3500 was in neutral with the boat still on trailer backed into the lake, have yet to drive the buggar lol, have replaced the manifold and a dodgy cooling pipe so will give it a run at the weekend..

 

[Bondo]

Re: rev limits of volvo 4.3

WOT rpms are Meaningless unless the engine is under Load.....<br /><br />Get her buttoned up,+ Splash It,....... Then see what she'll do WOT underway......That's the #s you're looking for......

 

[rob935]

Re: rev limits of volvo 4.3

yip makes sense bondo thanks, just very anxious looks like i bought a pile of crap so far lol...have new manifold on however the battery is shot so picking up new one tomorro so will give it a splash on fri evening and will let you know thanks again..

 

[rob935]

Re: rev limits of volvo 4.3

new battery works a treat manifold perfect and she runs like a dream HUGE difference, back to the rpms she is still only going as far as 3500 and is doing 40 to 45 mph at that?? does this sound ok ?? thought the rpms a bit low yet speed is ok ? any thoughts...

 

[tommays]

Re: rev limits of volvo 4.3

I would say eather your tack or speedo is worng <br /><br />45 MPH at 4800 RPM would be very good performance<br /><br />45 at 3500 is not going to happen<br /><br />tommays

 

[bruceb58]

Re: rev limits of volvo 4.3

Why would you say 45 at 3500 can't happen without knowing the size/weight of the boat?<br /><br />I do agree with you that a double check with a known good tach would be worthwhile.

 

[rob935]

Re: rev limits of volvo 4.3

have a speedo on dash but also have one on the depth/fish finder which just about agrees with the one on the dash....would the rev counter be faulty..??

 

[tommays]

Re: rev limits of volvo 4.3

Show me any boat any with a stock 4.3 that can do 45 MPH at 3500 RPM<br /><br />It takes way more HP than that motor can make at that RPM to go 45 MPH even if it was in a light 18' boat<br /><br /><br />tommays

 

[rob935]

Re: rev limits of volvo 4.3

the boat is a 92 wellcraft 20ft bowrider ??

 

[bruceb58]

Re: rev limits of volvo 4.3

OK...I doubt both values.

 

[rob935]

Re: rev limits of volvo 4.3

the speed i am sure is accurate its the rpms that dont seem right??

 

[bruceb58]

Re: rev limits of volvo 4.3

Hmmm...have you checked the switch on the back of the tach to see if it's pointing at 6 cylinders vs 8? if you multiply 3500 by 8/6 you get around 4600 RPM.<br /><br />I re-read your previous post that you had your fishfinder reading your speed. I believe that is accurate as well. I never ever trust the pitot tube type.

 

[bruceb58]

Re: rev limits of volvo 4.3

 

[rob935]

Re: rev limits of volvo 4.3

thanks bruce didnt think of that will check it out at the weekend sounds like that may be the answer...

 

[Gary H NC]

Re: rev limits of volvo 4.3

I know my 4.3 at WOT of 4500 rpms is running about 45mph..Using a 21 pitch prop.

 

[rob935]

Re: rev limits of volvo 4.3

thanks gary that sounds about right my prop has the same pitch so im convinced the rev counter is on the wrong setting..?

 

[QC]

Re: rev limits of volvo 4.3

Sounds like the tach switch to me too. Old owner probably never knew any different . . . I have seen it set improperly on a new boat

 

[rob935]

Re: rev limits of volvo 4.3

yes guys the rev counter had the wrong setting at the back so its all sorted now and seems to be running really well, got 52 mph at 4800 rpm so very pleased with performance.