Top Speed Of Our Boat?

[LuvBoating]

For reference, our boat, a 1992 Crownline 196BR...so just a tad smaller than yours weighs in at about 4,000 when completely full of fuel, 5 people and gear.
We have a 5.0LX (GM 305), Rochester 4 BBL carb, motor has 331 hours on it now, and have had it up to 40mph (GPS) at around 3800rpm or so, with room to move on the tach/throttle. I imagine my top end speed would be about 47mph with the load we carry. Previous owners have had it up to 52mph with a little more than half a tank of fuel and 3 adults.
That is also with a Mercury 19P 3-blade prop.
Something is going on and you are getting good advice here..keeping hunting the issue.

Our boat is a 20 foot Cuddy Cabin. Only my wife and I ride in it, with only some gear under the bench seat. The engine is a Chevy 350 5.7L 1992 Mercruiser I/O w/a Rochester 4BBL carb. The block only has 25 hours on it. Top speed, we've had it, is 28/29 mph. We are in our early 70's and really don't want to go any faster, but would like to know the top speed the boat could go. The prop is a Quicksilver 19P 3-blade.

 

[LuvBoating]

if you never run the tank out, your adding stabil to old gas with stabil in it. since you stated your tank is the same fuel since 2017, what you have in the tank is no-longer fuel. come spring, it will most likely turn to sludge/varnish. then the only cure would be to mechanically clean the tank, pulling the pickup tube and AS valve and rebuilding your carb.

Remember, our tank is no long completely full. We have used up 1/2 of the tank. We will be adding Star Tron Fuel Treatment to the new gas after it's put in. Anyway, guess we'll just have to see what happens next Spring. If the engine starts up ok, then we will be ok. If not, we'll have to go from there.

 

[JASinIL2006]

If the boat is still in the water, I'd try to run as much gas out of it before you have it winterized. Adding fresh gas to a tank that's only 1/8 full will have a much different affect than adding fresh gas to a tank that's half full of bad gas, no matter what additives you pour into it.

 

[Horigan]

LuvBoating, Your boat should be able to hit at least 45 mph. I have a 21' cuddy with a 302 and get that at 4400 rpm. You likely have a fuel flow problem, which is likely due to old gas clogging your carb and other fuel system components. Your gas is about to turn into a very difficult to remove substance, hence all the advice to get it out now.

 

[LuvBoating]

If the boat is still in the water, I'd try to run as much gas out of it before you have it winterized. Adding fresh gas to a tank that's only 1/8 full will have a much different affect than adding fresh gas to a tank that's half full of bad gas, no matter what additives you pour into it.

Boat sits on it's trailer, outside, at a Boat/RV Storage. We are only going to put it on the water one more time, then we will prepare it to be winterized by local marine service.

 

[LuvBoating]

LuvBoating, Your boat should be able to hit at least 45 mph. I have a 21' cuddy with a 302 and get that at 4400 rpm. You likely have a fuel flow problem, which is likely due to old gas clogging your carb and other fuel system components. Your gas is about to turn into a very difficult to remove substance, hence all the advice to get it out now.

Well, so far the gas has been fine, since filling the tank in August 2017. Just hard to start, after a week or so of sitting. It has a carburetor, not EFI or electric fuel pump. But, once started/stopped, it pretty much starts right up again. Getting up on plane..........no problem at all. It cruises right along at 29 mph.

 

[LuvBoating]

The gas that's in the tank is 100% non-ethanol from the marina next to the dry storage we had in Florida. I've read online that this gas should only last 6-months, but ours has lasted 3 years of last month.

Talked to a distributor of BG44K Fuel System Cleaner and they highly recommend us putting two cans in next Spring. She told me "you'll be shocked at how much better your engine will run........guaranteed". Well, that along with re-jetting the carb and carb adjustment (hopefully) will do the trick. Now, I did say the word "hope". As far as the prop goes, will find out if we have the right prop on it.

 

[Scott Danforth]

Talked to a distributor of BG44K Fuel System Cleaner and they highly recommend us putting two cans in next Spring. She told me "you'll be shocked at how much better your engine will run........guaranteed".

get that in writing. because 99% of additives are snake oil.

 

[LuvBoating]

And, for the forum member that was asking about our boat transport to northern Colorado: First, we put all new tires on the trailer as well as new stern straps. The money we got from selling our 1997 Dodge RAM 1500 pickup, we used to pay a private transporter to haul our boat here. The boat made it just fine. Cost: $3,500 and well worth the cost.

 

[mr 88]

Well.........when we have it winterized, or next Spring "summerized", we will ask the marine service if we have the correct prop on.

From what we know, the prop that is on the boat now, is the correct one. A marine mechanic installed it and didn't say a word about it being the wrong prop. We could have the wrong prop on it, but have to rely on a marine mechanic looking at the prop and telling us. The number of the prop that is currently on it is: 1916P19 Quicksilver. If that's not the correct one, then we have to rely on local boat mechanic to tell us that.

What part of ahicks reply did you not understand ? A prop specialist , marine mechanic or boat salesman cannot tell you that your prop is correct without the info that ahicks told you . The statement about you moving to Colorado has everything to do with jetting of your carbs because of the higher altitude your operating in , nothing to do with transporting or the large amount of money you spent to have it transported.

 

[Rmountainharley52]

What lakes are you using your boat on? I live just south of Denver I can tell you elevation plays a big part in how well your boat performs. Our previous boat was a 1999 Caravelle 209 bowrider at 21" with a 5.0L v8 and I have had it up to 40mph at chatfield res just SE of Denver which is at about 5500ft. with a 19p prop and around 4400rpms. Taking that same boat down to Elevenmile res at closer to 8500ft and I had to drop the prop pitch down to a 17p also my top speed dropped down to around 35 mph.

 

[ahicks]

Well.........when we have it winterized, or next Spring "summerized", we will ask the marine service if we have the correct prop on.

From what we know, the prop that is on the boat now, is the correct one. A marine mechanic installed it and didn't say a word about it being the wrong prop. We could have the wrong prop on it, but have to rely on a marine mechanic looking at the prop and telling us. The number of the prop that is currently on it is: 1916P19 Quicksilver. If that's not the correct one, then we have to rely on local boat mechanic to tell us that.

A "marine mechanic" cannot walk on water. Until he can, he's (or somebody!) going to need to know the tach reading with the current prop to tell you if it's the right one or not. It really is that simple. No shortcuts.

 

[LuvBoating]

What part of ahicks reply did you not understand ? A prop specialist , marine mechanic or boat salesman cannot tell you that your prop is correct without the info that ahicks told you . The statement about you moving to Colorado has everything to do with jetting of your carbs because of the higher altitude your operating in , nothing to do with transporting or the large amount of money you spent to have it transported.

IOW, we have the same type/prop number/pitch that was on the boat when we bought it in northeastern Florida. The prop may not be the right one for here, at 4,984 ft., but if it's the one a manual calls for, at this elevation, we'll keep it on. Earlier this summer, I did look up the prop number of the prop we have on and it was the correct one for the elevation here. Will re-check.
Yes, compared to some quotes we got, it was a large amount of money for transporting, but the gentleman had great references and got our boat here safely. To us, the cost was well worth what we paid.

 

[LuvBoating]

What lakes are you using your boat on? I live just south of Denver I can tell you elevation plays a big part in how well your boat performs. Our previous boat was a 1999 Caravelle 209 bowrider at 21" with a 5.0L v8 and I have had it up to 40mph at chatfield res just SE of Denver which is at about 5500ft. with a 19p prop and around 4400rpms. Taking that same boat down to Elevenmile res at closer to 8500ft and I had to drop the prop pitch down to a 17p also my top speed dropped down to around 35 mph.

First, when we lived here in Colorado before, for 5 1/2 years, we had a 1989 16' Invader Bowrider w/a Volvo Penta 4-cylinder engine, lived in Parker and boated on Chatfield quite a bit. Also went on Cherry Creek Reservoir a few times. To be honest, we didn't even know what pitch the prop was on our old Invader Bowrider, but I did get two skiers up on Cherry Creek.

If you are buzzing around Chatfield on a prop pitch of 19p, then I'd think that the pitch prop of 19p we have, would be fine on Boyd Lake here. But, I could be wrong.

 

[LuvBoating]

A "marine mechanic" cannot walk on water. Until he can, he's (or somebody!) going to need to know the tach reading with the current prop to tell you if it's the right one or not. It really is that simple. No shortcuts.

Well, when the owners of a boat are more into "computer stuff" and the western/cowboy-cowgirl-rodeo types than marine mechanics, a marine mechanic can, without a doubt, to us, can "walk on water".

 

[JimS123]

When I got my first boat (brand new) and was employed as a computer geek and didn't know a bow from a stern, the dealer's salesman suggested that we tach the boat to see if it came from the factory with the correct one. After the initial break-in period, we did just that. It wasn't. They put the correct one on at no charge to me. My third new boat had the same problem. Once again the factory screwed up. This time, though, I was able to re-pitch it and got perfect performance.

Boy, I hate to think how bad a used boat could be propped.....LOL.

Right now you have fully crapped gas. If you fill the tank like you said, next Spring your gas will only be half crap. If you drain it now and fill in the Spring it will be good gas. If you leave the gas and fill in the Spring, it still won't be good, but at least it'll only be quarter crap.

You have a fuel problem. Undoubtedly partly due to crap gas, partly due to not being adjusted for elevation, and possibly a simple used carb that's not functioning properly.

You may have a prop problem, but that won't be known until the boat is running well and you can get the required data. Mercury Marine has a prop selector computer program that will tell you everything you need to know, so you don't have to rely on advice from others that may or may not know what they are talking about. (google it)

Your boat should run in the low 40 mph range. It doesn't matter that you only want to go 25. If the engine is not performing properly you are wasting fuel and not doing the engine any good.

There has been a lot of good input in this thread. Take the advice, or do what's easy for you. But if you don't follow the logical suggestions, don't complain that it doesn't run right next year.

 

[ahicks]

Well, when the owners of a boat are more into "computer stuff" and the western/cowboy-cowgirl-rodeo types than marine mechanics, a marine mechanic can, without a doubt, to us, can "walk on water".

You did ask for help regarding the performance of your boat. You have been given enough info here to at least start asking questions of the right people, how to do it yourself, or just live with what you have.

As somebody that retired after 25 years or so in IT, one of the things I learned about anything new (which was frequently!), was going to be to ask questions, frequently! At least until I understood enough about the issue to teach myself more. Best of luck....

 

[LuvBoating]

When I got my first boat (brand new) and was employed as a computer geek and didn't know a bow from a stern, the dealer's salesman suggested that we tach the boat to see if it came from the factory with the correct one. After the initial break-in period, we did just that. It wasn't. They put the correct one on at no charge to me. My third new boat had the same problem. Once again the factory screwed up. This time, though, I was able to re-pitch it and got perfect performance.

Boy, I hate to think how bad a used boat could be propped.....LOL.

Right now you have fully crapped gas. If you fill the tank like you said, next Spring your gas will only be half crap. If you drain it now and fill in the Spring it will be good gas. If you leave the gas and fill in the Spring, it still won't be good, but at least it'll only be quarter crap.

You have a fuel problem. Undoubtedly partly due to crap gas, partly due to not being adjusted for elevation, and possibly a simple used carb that's not functioning properly.

You may have a prop problem, but that won't be known until the boat is running well and you can get the required data. Mercury Marine has a prop selector computer program that will tell you everything you need to know, so you don't have to rely on advice from others that may or may not know what they are talking about. (google it)

Your boat should run in the low 40 mph range. It doesn't matter that you only want to go 25. If the engine is not performing properly you are wasting fuel and not doing the engine any good.

There has been a lot of good input in this thread. Take the advice, or do what's easy for you. But if you don't follow the logical suggestions, don't complain that it doesn't run right next year.

So far, this summer, after taking it out three times and cruising around local lake at 28 mph, the engine was running fine on plane. It was just after I tried to get more speed up with the throttle that the engine would begin to bog down. IOW, the gas in the tank is 3 years old, but the way the boat cruised at 28 mph, around the lake three different times, a person really wouldn't think the gas was three years old.

If the gas is that crappy, as you say it is, why would the boat cruise on plane so nicely???? I'll be there are plenty of boaters out there that have gas in their tanks, and running the boat, in older gas than we even have. There are those that simply can't use up a tank full of gas in a summer and can't afford to empty the tank out. They know their gas is old, but can only use what they can and fill the tank for winter.

 

[LuvBoating]

We, wife and I, really do appreciate all the recommendations and we will research them.

The boat tank was completely emptied, by the marine service we had in Florida, in July 2017. That gas had been in the tank since March 2012.............that's 5 years! So, during that 5 years, we did run the boat on the St. John's River (Jacksonville, FL) a few times. The boat ran "ok" during those times, but we knew that we were running on old gas and decided to have it drained. Luckily, the marine service didn't charge us for draining the tank.

So, the gas that's now in the tank (1/2 tank) we will simply have to use it up with the new gas we will fill the tank with. We just haven't got a choice. And, without a doubt, I'm sure that 5 year old gas looks much worse than 3 year old gas that we currently have. We always have a full tank before winterizing.

 

[Alumarine]

Seeing you don't use much fuel maybe don't fill the tank at the end of the year?