Wrong New Prop Or What?

[LuvBoating]

1992 Celebrity 200 Cuddy Cabin. Mercruiser engine w/5.7L V8 I/O. Had it transported up here to northern Colorado in 2019, from northeast Florida aka Jacksonville. Before leaving Jacksonville, had new freshwater anodes put on the drive, but did not change the prop. We didn't know that the prop had to be changed due to the higher elevation here that is 5,000 feet. The first time we took our boat to local lake, with 19P prop on, we could only get WOT 2,200 rpm's out of it. Any more throttle and the engine would start to bog down.

So, for Spring "summerization" this year (2021), we had a new Mercury Black Max 17P prop put on. Due to different reasons, we weren't able to take the boat out until yesterday (Oct 8th). Got out of lake, to do WOT, and while opening up the throttle, the boat started to bog down and almost stop. We thought, "they put on the wrong size of prop or then engine needs tuned up or both."

We should be getting up to 4,600 rpm, which is more than double the 2,200 we got with the 19P prop. And, with the new prop, I think I could run faster than the boat was going! I know that our RPM's must have been very, very low and yet I had the throttle 3/4 down.

Please, any ideas/suggestions/recommendations? Thanks

 

[GA_Boater]

I wouldn't jump on the prop. The prop may affect WOT RPM by about 500 RPM. The motor is probably running poorly and needs some diagnostics done.

This should be back where you started. Please don't move threads because you can't.

 

[LuvBoating]

I wouldn't jump on the prop. The prop may affect WOT RPM by about 500 RPM. The motor is probably running poorly and needs some diagnostics done.

This should be back where you started. Please don't move threads because you can't.

I deleted because I seen the forum part about props and I figured I put the thread in the wrong area. So, I moved it, but if it can be here, fine with me.

Guess, when we take it in next Spring, will have a check done on it and, if needed a tune-up. But, will ask the marine service if indeed this is the correct prop. When the engine was run, after "summerization" the mechanic stated on the invoice that the engine was fine.
Funny, but when we had the 19 pitch prop on, and the last time it was in the water, Oct 2020, the engine was running fine, just not getting the WOT rpms we should. That's when we were told that we needed to change the prop for a higher elevation. So, they put on the 17 pitch one, but just don't know.

 

[nola mike]

How long between runnings in FL vs. Co? Like, move from Florida and then not use it again till the next spring?

 

[LuvBoating]

Last summer (2020) we took it out four times. We had way to much wildfire smoke at times last summer and, we simply aren't as young as we were when we lived here in Colorado before. We are now, 72 and 73.
When we were in Florida, we took it out sometimes during the summer there, but, again, wildfire smoke and tides ruled us for when we could take the boat out.
Even in Florida, we had the boat "winterized" and didn't use until the following Spring, just like we do here.

 

[tank1949]

1992 Celebrity 200 Cuddy Cabin. Mercruiser engine w/5.7L V8 I/O. Had it transported up here to northern Colorado in 2019, from northeast Florida aka Jacksonville. Before leaving Jacksonville, had new freshwater anodes put on the drive, but did not change the prop. We didn't know that the prop had to be changed due to the higher elevation here that is 5,000 feet. The first time we took our boat to local lake, with 19P prop on, we could only get WOT 2,200 rpm's out of it. Any more throttle and the engine would start to bog down.

So, for Spring "summerization" this year (2021), we had a new Mercury Black Max 17P prop put on. Due to different reasons, we weren't able to take the boat out until yesterday (Oct 8th). Got out of lake, to do WOT, and while opening up the throttle, the boat started to bog down and almost stop. We thought, "they put on the wrong size of prop or then engine needs tuned up or both."

We should be getting up to 4,600 rpm, which is more than double the 2,200 we got with the 19P prop. And, with the new prop, I think I could run faster than the boat was going! I know that our RPM's must have been very, very low and yet I had the throttle 3/4 down.

Please, any ideas/suggestions/recommendations? Thanks

I would expect carburetor needs to be adjusted for high altitude?

 

[Rick Stephens]

I would even more suspect water in fuel, dirty carburetor innards and crudded up filters.

 

[nola mike]

2" of prop isn't going

I would even more suspect water in fuel, dirty carburetor innards and crudded up filters.

That's why I was asking time between runs. If it worked fine in FL, then didn't a week later in Co that's a different story than if it sat a season

 

[achris]

Florida fuel and Colorado fuel are also going to be different (think summer fuel vs winter fuel). As well as going through the fuel system the fuel in the tank needs to be drained.

 

[LuvBoating]

Florida fuel and Colorado fuel are also going to be different (think summer fuel vs winter fuel). As well as going through the fuel system the fuel in the tank needs to be drained.

First, we never got the boat up to WOT in Florida. There was no need for it.
The first four times we took the boat out here (northern Colorado) it ran fine.

However, we wanted to use up some old Florida gas, which the tank was full of, so that's why we decided to go WOT on local lake once during the summer of 2020. At that time, we had a 19 pitch prop on, got the boat up to 2,200 rpms and "tried" to go WOT, but the engine started bogging down when I pushed the throttle higher. We knew something was wrong, when the engine started bogging down. We were told that we needed the carb re-jetted for the higher elevation here, but our marine service told us they don't do that. We also had no way to get all of the Florida gas out of the tank, except for driving around the lake a number of times. So, one the tank gas was 1/2 used, before 2020 "winterization" we filled the other 1/2 tank with Premium Sinclair gas.

So, it appears now that our only alternative is: if the marine service will adjust the carb (somehow) and put another 19 pitch prop back on. Getting 2,200 rpms out of the engine, is much better that what we got this past Friday. We won't get the full 4,600 rpms out of the engine we should, but. We don't go WOT on the lake anyway. Just use the boat to do a little cruising and fishing.

 

[LuvBoating]

I would even more suspect water in fuel, dirty carburetor innards and crudded up filters.

That was all checked and taken care of during our last "summerization" at the marine service. The mechanic told us the engine was fine, but that was only running on "muffs", not WOT on water.

 

[LuvBoating]

I would expect carburetor needs to be adjusted for high altitude?

If you mean, "re-jetted", the marine service we go to, and the only one within many miles that will service a 1992 boat, they don't do that. Now, adjusting the carb, they could, and I think they have already.

 

[nola mike]

The first four times we took the boat out here (northern Colorado) it ran fine.

So your problem isn't with prop or jetting or the carb.

However, we wanted to use up some old Florida gas, which the tank was full of, so that's why we decided to go WOT on local lake once during the summer of 2020. At that time, we had a 19 pitch prop on, got the boat up to 2,200 rpms and "tried" to go WOT, but the engine started bogging down when I pushed the throttle higher.

Sounds like you have bad gas or crud in your carb.

So, it appears now that our only alternative is: if the marine service will adjust the carb (somehow)

Rebuild after changing fuel filters and at minimum checking the condition of your gas

and put another 19 pitch prop back on. Getting 2,200 rpms out of the engine, is much better that what we got this past Friday.

Not really. Still isn't running right at best, and doing long term damage at worst. If it won't hit 2200 with a 17 it will do worse with a 19

Forum won't let me properly respond, my comments are interspersed above

 

[LuvBoating]

nola mike: Last summer, when we had the 19P prop on, we couldn't get the engine up to WOT, but did get it up to 2,200 rpms. I'd go to push the throttle down more, for more speed and it would start to bog down and I'd have to bring the throttle back to 2,200 rpms. The boat was cruising along nicely at that speed, but still wouldn't go to WOT. We were told that the prop was for a much lower elevation and we needed a new one for elevation of 5,200 ft., plus have the car re-jetted. And, as already stated, the marine service told us they don't re-jet carbs. So, we did have a new prop put on (17P), but, after having the boat out last Friday, the 17P wouldn't even get us up to 2,200 rpms. So, we figure we need another 19P and the carb adjusted the best the marine service can.

This is why we are saying that getting 2,200 rpms back is better than what we are getting now. If we can find a carb place that will re-jet the carb, will have it done, but if not, will simply have to settle with the 19P and 2,200 rpms.

As far as the gas goes, there is no way/no where, and I do mean "no way/no where, we can have the tank drained. Have already checked. When we lived in Florida, we had it done, but the marine service had a large tank to put the old gas in. So, if there is "no way/no where" to do this, have to use the gas that's in the tank (and hope for the best).

 

[nola mike]

nola mike: Last summer, when we had the 19P prop on, we couldn't get the engine up to WOT, but did get it up to 2,200 rpms. I'd go to push the throttle down more, for more speed and it would start to bog down and I'd have to bring the throttle back to 2,200 rpms. The boat was cruising along nicely at that speed, but still wouldn't go to WOT. We were told that the prop was for a much lower elevation and we needed a new one for elevation of 5,200 ft., plus have the car re-jetted. And, as already stated, the marine service told us they don't re-jet carbs. So, we did have a new prop put on (17P), but, after having the boat out last Friday, the 17P wouldn't even get us up to 2,200 rpms. So, we figure we need another 19P and the carb adjusted the best the marine service can.

This is why we are saying that getting 2,200 rpms back is better than what we are getting now. If we can find a carb place that will re-jet the carb, will have it done, but if not, will simply have to settle with the 19P and 2,200 rpms.

As far as the gas goes, there is no way/no where, and I do mean "no way/no where, we can have the tank drained. Have already checked. When we lived in Florida, we had it done, but the marine service had a large tank to put the old gas in. So, if there is "no way/no where" to do this, have to use the gas that's in the tank (and hope for the best).

Prop isn't your problem. Fuel/carb is by far the most likely culprit at this point. I wouldn't think a rejet is the solution by itself, but I don't have any altitude experience. If you only got 2200 rpm with a 19p and it was worse with a 17p, something is wrong

 

[LuvBoating]

Prop isn't your problem. Fuel/carb is by far the most likely culprit at this point. I wouldn't think a rejet is the solution by itself, but I don't have any altitude experience. If you only got 2200 rpm with a 19p and it was worse with a 17p, something is wrong

Yes, we know something is wrong, BUT, even if we only get 2200 rpm with a 19p, and the carb get adjust the best the marine service can, than we can't do much-to-anything more. We'd love to get the total 4600 rpm, that we should get, but we don't go that fast on local lake anyway.

From what we have know, from other boaters at local lake, nobody has a powerboat they brought up here from down south (Florida or surrounding states). All boats are from around here.

I'm starting really wonder if we need a new (rebuilt?) carb. I'm sure our marine service/parts could get us a new carb and install it for us. Think that could work?

 

[Rick Stephens]

Yes, we know something is wrong, BUT, even if we only get 2200 rpm with a 19p, and the carb get adjust the best the marine service can, than we can't do much-to-anything more. We'd love to get the total 4600 rpm, that we should get, but we don't go that fast on local lake anyway.

From what we have know, from other boaters at local lake, nobody has a powerboat they brought up here from down south (Florida or surrounding states). All boats are from around here.

I'm starting really wonder if we need a new (rebuilt?) carb. I'm sure our marine service/parts could get us a new carb and install it for us. Think that could work?

I gotta tell ya, unless “the best marine service” took the carb apart, rebuilt it and recalibrated it with proper jets, they didn’t do much of anything to be called “adjusted”. There are two adjustments on the outside of a carburetor. - idle mixture and idle speed. That’s it. Neither one has the least effect on operation once your throttle is open.

You might find you are going from the frying pan into the fire swapping to a rebuilt. They often are worse than the original and almost never are calibrated to your motor.

Please note, I get it that you want information on how to fix this, but you are also setting restrictions that your repairs are only to be done at the best marine service in your area. This forum is mostly a DIY Hangout. Since you only are going to take it to the one given service center, and they won’t do much of anything to fix you up, I think you are wasting your time here.

 

[achris]

1992 Celebrity 200 Cuddy Cabin. Mercruiser engine w/5.7L V8 I/O. Had it transported up here to northern Colorado in 2019, from northeast Florida aka Jacksonville. Before leaving Jacksonville, had new freshwater anodes put on the drive, but did not change the prop. We didn't know that the prop had to be changed due to the higher elevation here that is 5,000 feet. The first time we took our boat to local lake, with 19P prop on, we could only get WOT 2,200 rpm's out of it. Any more throttle and the engine would start to bog down.

That CLEARLY indicates an engine problem, not a propeller problem.

Doing the numbers on that boat, engine and prop, it should be pushing you EASILY. Even if it was too big, it would only drop the engine RPM to around 4,000, not 2,200. If it was a 'prop too big' problem, with a 19", you'd need to come up 2,400rpm, at 200rpm/in, you'd need a 7" prop... Frankly, that's laughable.

... but we don't go that fast on local lake anyway.

That is completely irrelevant! If the engine isn't able to make the recommended RPM at WOT, then it's a) overloaded, and that means it's overloaded AT ALL RPM, and that leads to blown engines (head gaskets, holes in pistons, tulipped valves, etc), or b) there's something fundamentally wrong with the engine (low compression, poor fuel supply, weak spark, not advancing the timing)...

Your 'best service centre in the area' isn't doing the right thing. Go and buy a compression gauge and a timing light, and start doing what they should have done, a compression test and check the timing.... Either that or find another service centre, because this one is waiting for the engine to hand-grenade (which it WILL!), and then charge you a HUGE amount to repair or replace it.

Chris........

 

[LuvBoating]

I gotta tell ya, unless “the best marine service” took the carb apart, rebuilt it and recalibrated it with proper jets, they didn’t do much of anything to be called “adjusted”. There are two adjustments on the outside of a carburetor. - idle mixture and idle speed. That’s it. Neither one has the least effect on operation once your throttle is open.

You might find you are going from the frying pan into the fire swapping to a rebuilt. They often are worse than the original and almost never are calibrated to your motor.

Please note, I get it that you want information on how to fix this, but you are also setting restrictions that your repairs are only to be done at the best marine service in your area. This forum is mostly a DIY Hangout. Since you only are going to take it to the one given service center, and they won’t do much of anything to fix you up, I think you are wasting your time here.

First, I do very little in the form of repair/maintenance to our boat, so my DIY is basically nothing. I'm into using a computer and very little-to-no mechanic stuff at all. Now that I got that out of the way.............

This is the second carb the boat has had. The one that came on the boat, when we bought it in March 2009, had been rebuilt just prior to us buying the boat. In 2016, we got a new/rebuilt carb from National Carburetor in Jacksonville, FL.. Our marine service there installed it. The manifolds/risers were new in 2011, new block in 2012 (along with new alternator, belts, spark plugs) and new parts in outdrive in 2016. Everything done in Florida.

Until moving back to Colorado, we had never done the WOT before and, like I've already said, the only reason we "tried" it here was to use up some old Florida gas.

All we know is that it ran fine, other than getting it up to WOT, summer of 2020. We have 27.5 hours on the new block, that was installed in 2012.

All I'm looking for here is some kind of recommendation, but if those "recommendations" are the DIY type, I don't and am not about to try. I trust a marine service mechanic that has the experience I don't have. Nothing else I can do.

 

[LuvBoating]

That CLEARLY indicates an engine problem, not a propeller problem.

Doing the numbers on that boat, engine and prop, it should be pushing you EASILY. Even if it was too big, it would only drop the engine RPM to around 4,000, not 2,200. If it was a 'prop too big' problem, with a 19", you'd need to come up 2,400rpm, at 200rpm/in, you'd need a 7" prop... Frankly, that's laughable.


That is completely irrelevant! If the engine isn't able to make the recommended RPM at WOT, then it's a) overloaded, and that means it's overloaded AT ALL RPM, and that leads to blown engines (head gaskets, holes in pistons, tulipped valves, etc), or b) there's something fundamentally wrong with the engine (low compression, poor fuel supply, weak spark, not advancing the timing)...

Your 'best service centre in the area' isn't doing the right thing. Go and buy a compression gauge and a timing light, and start doing what they should have done, a compression test and check the timing.... Either that or find another service centre, because this one is waiting for the engine to hand-grenade (which it WILL!), and then charge you a HUGE amount to repair or replace it.

Chris........

Since I do very little DIY stuff on our boat, wife and I have to completely trust the only marine service here that will work on a 1992 boat. Our last marine service in Florida, told us that our boat was definitely the oldest boat they'd work on. IOW, they were doing us a favor by working on it.

When we take the boat in next Spring, for "summerization", I will ask the service if our carb needs to be re-jetted. If they say "yes", but don't do that type of work, than may have to buy a new carb from here. At least a carb bought here should be ready for the 5,000 ft. level/elevation here.

We changed the anodes to "freshwater" ones, but didn't know about re-jetting a carb for high elevation (5,000 ft.). Guess nobody that owns a powerboat moves from Florida up to Colorado or surrounding states. We did, but that's us.