Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

[ceasarea]

I just bought it and it runs like new....It's very clean.It has a 14 by 21 prop....Fast out of the water and runs 46MPH with 5 adults and two kids.....By myself and a full tank of gas it goes about 52-53 MPH according to the speedometer.It runs at idle around 800RPM and at full speed 4800 to 5000 RPM's. Are those numbers in the correct range. Also i plan on having it winterized and will install synthetic oil....Thanks for all your help.,

 

[craze1cars]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

I think proper full throttle RPM range is 4,200 to 4,600 for that motor. If so, it sounds like you're over-revving it. Best to contact a Volvo dealer and confirm, or post a question over in the Volvo subsection and see if someone knows the answer. Correct range might even be printed on the data plate on your engine...have you looked?

Also one of your numbers is likely not accurate, might be wise to double-check some. Using prop slip calculator, assuming you have a 1.97 gear ratio (which is an assumption, but I believe common on 4.3GL's), if you're turning 4900 rpm, 52 mph, 1.97 gear ratio, 21 pitch prop it means you have -5% silp, which is mathematically impossible. If a GPS reveals your actual top speed is closer to 45 or 46, then that is realistic at about 10%.

Or...maybe you have a different gear ratio...something in the 1.75 range would make sense with your numbers, but I don't know what Volvo offered in all these machines.

Maybe your speedo is reading too high. Maybe tach reading too high. I dunno. But if you're truly spinning near 5,000 rpms it's probably OK for an occasional run and will certainly give you excellent hole-shot and weight-carrying ability, but you might want to not do long light-load high speed runs too often because max recommended rpm for that engine I THINK is 4600. But 5,000 won't hurt it every once in a while.

Maybe someone else here can confirm some of these numbers, but like I said, you're more likely to find a good source over in the Volvo repair section of this thread.

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Thanks so much.....i really appreciate it...

 

[jestor68]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

You can go to the VP web site and down load the owner manual for your engine. It's in the engine data base section.

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Whats Vp web site....volvo?

 

[airdvr1227]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

4600

 

[bunker108]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Yup, 4600 but I spin my 98 4.3GL to 4800 for short blasts regularly. I have had it over 5000 doing prop testing. The 4.3s are tough little engines and the SX drives can handle much more power. The carbed 4.3s just don't breath up in the higher revs. Mechanically they are fine up in the higher range of RPM but torque really starts falling off.

 

[jestor68]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Whats Vp web site....volvo?

Google "Volvo Penta Marine Lesiure Engines", and select the Lesiure engines item after "web results" down the page.

Depending on which site you end up on, on the feft site map, select either "engine data base" or "find your engine", and it'll take you to the page to find your engine by filling out the information asked for.

Once you select your engine, there are little icons below to open a PDF of the owner manual, and you can print it out.

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

I can see by research that my engine WOT is 4600....I am running a 14.25 by 19 prop.....I believe you drop 200rpm's ( some say 300 to 400 ) by increasing the pitch by one size....so i would assume if i go to a 21" pitch it would solve the problem....I also assume i might loose some top end speed...Right now it seems i am revving between 4900 and 5000 at WOT. Am i correct ?
Thanks

 

[craze1cars]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

I can see by research that my engine WOT is 4600....I am running a 14.25 by 19 prop.....I believe you drop 200rpm's ( some say 300 to 400 ) by increasing the pitch by one size....so i would assume if i go to a 21" pitch it would solve the problem....I also assume i might loose some top end speed...Right now it seems i am revving between 4900 and 5000 at WOT. Am i correct ?
Thanks

Have you addressed the fact that some of your numbers you provided in post #1 are guaranteed to be inaccurate? Most importantly, if your tach is wrong, you shouldn't be prop shopping until it's verified accurate. You might actually be turning a perfect 4600 rpms with your current prop and not even realize it's perfect...

To answer your question...if, and only IF your tach is accurate...You are correct in considering a 21" pitch, if you stay in the same prop model/design. However you are not correct in assuming it will lose some top end speed. This would surprise me...it might actually gain a MPH or two. But it will definitely lose some of its holeshot capability.

If you want to come closer to maintaining your current excellent holeshot you might consider a 4 blade prop in a 19. The simple change from 19" 3 blade to 19" 4 blade might drop you down 200 RPM up top, while keeping your good holeshot and have minimal impact on top speed...but probably a 1 or 2 mph reduction.

Sometimes just getting a more aggressively designed/cupped prop in the same pitch will similarly drop your RPMS a few hundred, while adding overall performance & top speed. So if you're considering a high performance stainless prop with aggressive cupping to replace a stock aluminum prop, you might likewise be wise to stick with a 19" pitch. A 21" might be too much in an aggressively biting prop.

Remember these rules of thumb sometimes fail. Only a test-drive will answer for certain.

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Thanks for your help....I will stick with the 19 for water skiing and buy the 21 for everyday boating....Right now it seems like it jumps out of the water in 3 or 4 seconds....very fast.....great for skiing.....but i guess not so great for the engine.

 

[craze1cars]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Thanks for your help....I will stick with the 19 for water skiing and buy the 21 for everyday boating....Right now it seems like it jumps out of the water in 3 or 4 seconds....very fast.....great for skiing.....but i guess not so great for the engine.

I wouldn't say that it's not great for the engine. On the contrary. As long as you're not running for extended periods of absolute top speed, being under-propped is entirely harmless, and in fact beneficial because it doesn't lug it under heavy loads like watersports. Very common for boaters using their machines for watersports to underprop their boat a bit like yours likely is. Hurts nothing, is easy on the boat, and is easier on the skiiers. Just don't slam it to wide open throttle and hold it there for 20 mile straight runs to get somewhere...

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

Thanks for your help.....I am thinking i will most likely keep the same prop.......It was new when i bought the boat....It had a 21" pitch on it and the previous owner said it needed the smaller pitch to get it on plane faster....Thanks for all your advice...

 

[bunker108]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

My boat also came with a 21p 3 blade. I ran that prop all last season and it did well enough, but was sluggish out of the hole loaded. Once on plane I could still spin it to rated WOT. I switched to a 19p 4 blade and it has been a great prop for me and how we boat. I would like to try some SS 3&4 blade 19p. Maybe next year!

 

[ceasarea]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

I had the boat out for the last time last weekend...It was cool out and i am sure the water was too...It was used for about 45 minutes.The temp light seemed to go to about 140 and i could RPM it to about 5500.....although i brought it down to below 4500....Is that normal during cooler water temps> The prop is actually a 4 blade not a three blade...14.25 by 19. Thanks

 

[craze1cars]

Re: Whats the W.O.T for 1997 Glastron gs with 4.3gl volvo

What did your temp gauge show during warmer water times? Engine temp is controlled by thermostat, not water temp. Shouldn't matter if water is 33 degrees or 90 degrees...your water temp in the engine should be similar. T-stat on Volvos usually is rated at 160. If running much cooler than that, sometimes a sign that the t-stat is stuck partially open. When I had a Volvo I would periodically find a little silt/sand caught in the t-stat not permitting it to close all the way, this would cause temps to not get up to proper water temp. I'd pull t-stat, clean out silt, test in hot water on the stove to make sure it's opening at correct temp, and reinstall. Fixed. If you t-stat is original, and boat is presumably raw-water cooled, at 17 years old it's really time to just swap it out probably...

So now you can spin 5500? 2 weeks ago you were 4800 to 5000? Your first post says you were running a 21 prop. Later posts says you are running a 19...now blade count changes from 3 to 4. And your rpms have jumped 600 or better since first post. And if I'm understanding you correctly, this is all on the exact same prop?

So I'm completely confused LOL, so based on constantly changing data I have absolutely no idea if you need to re-prop or not... But if you can truly spin an engine rated at 4600 rpm to 5500 rpm, you are crazy-underpropped, or maybe ventilating badly. Really need accurate/repeatable data to make any recommendations or determinations.

I betcha dollars to donuts that yer 17 year old tach is also on the fritz...