View Full Version : Temperature/RPM problem
jchance
08-24-2009, 08:17 AM
I have a 2001 Maristar with an LTR 330HP engine. Yesterday it began to run rough and lose RPMs while overheating at the same time. The usual operating temp is around 160 degrees, but it would shoot to 205/210 degrees and the RPM would suddenly fall off if driving above 400 RPM. I suspect a raw water pump failure but did not have enough time last night to pull the cover and impeller. My son was able to drive back to the dock at mid-throttle without problems, but would have the same thing happen everytime he would try to go above 3500-4000 RPM.
If it is a pump failure, what else do I need to do besides replace the impeller or pump? My main concern is if the vanes broke off and landed somewhere else. Where else do I need to look if there are loose pieces floating around? Thanks!
TMCNo1
08-24-2009, 09:11 AM
I have a 2001 Maristar with an LTR 330HP engine. Yesterday it began to run rough and lose RPMs while overheating at the same time. The usual operating temp is around 160 degrees, but it would shoot to 205/210 degrees and the RPM would suddenly fall off if driving above 400 RPM. I suspect a raw water pump failure but did not have enough time last night to pull the cover and impeller. My son was able to drive back to the dock at mid-throttle without problems, but would have the same thing happen everytime he would try to go above 3500-4000 RPM.
If it is a pump failure, what else do I need to do besides replace the impeller or pump? My main concern is if the vanes broke off and landed somewhere else. Where else do I need to look if there are loose pieces floating around? Thanks!
Your engine may have the Limp Home mode that prevents the engine from obtaining higher rpm and will allow you to get to the dock or trailer w/o a severe/damaging overheat.
The impeller pieces are normally small and will pass thru the engines digestive track. Change the impeller and see what happens before disassembling the engine for no reason.
I have a 2001 Maristar with an LTR 330HP engine. Yesterday it began to run rough and lose RPMs while overheating at the same time. The usual operating temp is around 160 degrees, but it would shoot to 205/210 degrees and the RPM would suddenly fall off if driving above 400 RPM. I suspect a raw water pump failure but did not have enough time last night to pull the cover and impeller. My son was able to drive back to the dock at mid-throttle without problems, but would have the same thing happen everytime he would try to go above 3500-4000 RPM.
If it is a pump failure, what else do I need to do besides replace the impeller or pump? My main concern is if the vanes broke off and landed somewhere else. Where else do I need to look if there are loose pieces floating around? Thanks!
First of all, on a boat with only raw water cooling, there's no limp home mode, it's "Shut it the he!! off and wait until it cools down and you find the problem" mode. If it overheats with a radiator and closed cooling, some of the heat can still be carried away but once the coolant flow stops, SHUT IT DOWN! With no coolant flow, there's no such thing as "allow you to get to the dock or trailer w/o a severe/damaging overheat." It keeps you from running it at WOT while it's overheating and causing a catastrophic failure, but it still damages the motor and exhaust.
If the vanes break off, they may be full vanes, especially if the advice to not change the impeller for more than two year is followed. This is why MC and Indmar recommend annual impeller changes. If the vanes are gone but intact, they may be at the thermostat.
How long did you run it after it went into RPM REDUCTION MODE (that's the real name)?
bigmac
08-24-2009, 09:49 AM
Raw water pump failure is usually manifested by either a big stream of water coming from it, or a noticeable screeching sound from bearing failure. In your case, impeller likely toast. It will cost you about $35 to find out.
MariStar-Man
08-24-2009, 10:04 AM
Are you going to troubleshoot and fix problem yourself or take it to the Mc dealer?
JimN is a good guy, he is just a little high strung...:D
Are you going to troubleshoot and fix problem yourself or take it to the Mc dealer?
Jim is a good guy, he is just a little high strung...:D
I was a MC mechanic. I have seen just about every owner-implemented short-cut out there and I have read all kinds of "advice" from 'experts', that's so wrong it can kill a motor. You're the guy who bought a boat without running it and that's just not a good way to make sure it'll be a good purchase.
Do you always say things about people you don't know? If your car was overheating, would you keep running it, or shut it down?
jchance
08-24-2009, 11:06 AM
I appreciate everyones help but could do without the crap. I wasn't in the boat. My 22 and 17 year old sons were aboard, knew that there was a problem and immediately slowed and watched the gauges to make sure they returned to normal before trying to limp back to my pier. Right or wrong, they did what they thought best!
I have been around marine engines for the last 35 years and only wanted to know where the most likely hiding places are for broken pieces in this particular engine IF an impeller fragmentation caused the problem (which is what I think happened). BTW--this impeller has 12 months on it, is replaced annually and is due for replacement this fall when winterizing the boat and yes, I do my own repairs whenever possible.
Thanks for everyones help!
bigmac
08-24-2009, 11:20 AM
My understanding of the LTR engine is that most rubber trapping tends to be in the area of the two thermostats. If you pull the impeller and find big pieces gone, I guess I'd pull the RW output hose from its engine attachment and backflush through the thermostat housings.
kkkeating
08-24-2009, 11:28 AM
My understanding of the LTR engine is that most rubber trapping tends to be in the area of the two thermostats. If you pull the impeller and find big pieces gone, I guess I'd pull the RW output hose from its engine attachment and backflush through the thermostat housings.
I believe you're thinking of the LT-1 engine; the LTR only has one thermostat, at least my X-9 does.
I would think the majority of impellar parts would end up in the transmission cooler. Those that get through the cooler would end up at the thermostat.
My understanding of the LTR engine is that most rubber trapping tends to be in the area of the two thermostats. If you pull the impeller and find big pieces gone, I guess I'd pull the RW output hose from its engine attachment and backflush through the thermostat housings.
LTR only has one thermostat.
I appreciate everyones help but could do without the crap. I wasn't in the boat. My 22 and 17 year old sons were aboard, knew that there was a problem and immediately slowed and watched the gauges to make sure they returned to normal before trying to limp back to my pier. Right or wrong, they did what they thought best!
I have been around marine engines for the last 35 years and only wanted to know where the most likely hiding places are for broken pieces in this particular engine IF an impeller fragmentation caused the problem (which is what I think happened). BTW--this impeller has 12 months on it, is replaced annually and is due for replacement this fall when winterizing the boat and yes, I do my own repairs whenever possible.
Thanks for everyones help!
I wouldn't call it crap. You didn't tell us anything about your 35 years of experience with marine engines, just that it went into RPM reduction, so there was no way for anyone here to know. I posted in bold type because I'm really tired of people calling RPM reduction 'Limp Home Mode', when it has been covered here so many times, but being new (going by your post count), you wouldn't have seen that. That was directed less at you than others.
Does the water where you boat have much debris or weeds? Do you check the oil cooler often?
bigmac
08-24-2009, 11:43 AM
I believe you're thinking of the LT-1 engine; the LTR only has one thermostat, at least my X-9 does.
I would think the majority of impellar parts would end up in the transmission cooler. Those that get through the cooler would end up at the thermostat.
Yeh, was thinking of LT-1. In the LTR, indeed the pieces would be found in the transmission cooler stainer. Anything small enough to get through that would be flushed through the engine.
Yeh, was thinking of LT-1. In the LTR, indeed the pieces would be found in the transmission cooler stainer. Anything small enough to get through that would be flushed through the engine.
And anything larger will be stuck on the cooler, blocking the flow of water.
russlars
08-24-2009, 02:48 PM
When my impeller went out, I was able to locate a lot of the shards in the transmission cooler. Just take off the hose at the bottom and reach into the cooler with your finger and you should be able to get most of them out. There is a strainer in there which is designed to catch most of the debris out of the engine block.
bigmac
08-24-2009, 03:02 PM
And anything larger will be stuck on the cooler, blocking the flow of water.
Thus fulfilling the designated function of a "strainer".
jchance
08-24-2009, 03:07 PM
I am on the Tennessee River and yes, there is occasionally some floating debris. Never had anything get sucked in that caused a overheat situation before though. We see this with the PWCs but almost never with the other boats around here.
It will be a couple of weeks before I get back to our lakehouse to check out the problem but I will post the results. It sounds like the tranny cooler will be the most likely place to look if the problem is what I expect.
BTW-until a couple of years after I bought a Mastercraft, I did not know that this forum existed. It is a great resource; especially when looking for an answer that someone has already experienced.
As an aside--the fuel sender on the same boat always reads full. If I remove it and dry it out, then move it up and down in the tank, it functions perfectly. When I re-install it however, it goes back to reading full at any level. I am told by the sender manufacturer that it is most likely due to water in the tank. Does anyone have any pearls as to the 'easiest' way to remove water from the tank of a Maristar 210VRS?? I would prefer to not remove the entire tank if possible. The only thing that I can think is to run the tank down, pull the pump and suction out the remaining contents. Any other ideas?
Thus fulfilling the designated function of a "strainer".
Yeah but it would be nice if the surface area of the strainer was larger than the possible surface area of the impeller vanes.
I am on the Tennessee River and yes, there is occasionally some floating debris. Never had anything get sucked in that caused a overheat situation before though. We see this with the PWCs but almost never with the other boats around here.
It will be a couple of weeks before I get back to our lakehouse to check out the problem but I will post the results. It sounds like the tranny cooler will be the most likely place to look if the problem is what I expect.
BTW-until a couple of years after I bought a Mastercraft, I did not know that this forum existed. It is a great resource; especially when looking for an answer that someone has already experienced.
As an aside--the fuel sender on the same boat always reads full. If I remove it and dry it out, then move it up and down in the tank, it functions perfectly. When I re-install it however, it goes back to reading full at any level. I am told by the sender manufacturer that it is most likely due to water in the tank. Does anyone have any pearls as to the 'easiest' way to remove water from the tank of a Maristar 210VRS?? I would prefer to not remove the entire tank if possible. The only thing that I can think is to run the tank down, pull the pump and suction out the remaining contents. Any other ideas?
When you get there, go to the sender and look at the wires for anything that could be connecting them. If there's nothing, remove one wire and see if the gauge zeros out. If not, you may have a bad gauge. If it does zero out, look for adjustment screws/pots on the sender and try to adjust the one next to F (if it shows that).
If you can position the boat so the water can go to the lowest point, go and get a fuel line and primer bulb for an outboard motor, feed it to where the water is and pump it out. You may need to use a wire to make the hose go where you want.
Re: the manufacturer saying the gas may have water in it- these senders are accurate if adjusted in clean fuel and ANY contaminant will affect the accuracy. If you look into the tank and see foggy liquid at the bottom, remove it. That's the water/alcohol that has mixed and separated from the rest of the gas and it will definitely mess up the gauge's reading. It also isn't good to run the motor on that stuff- it definitely won't develop the power it should. Adding more alcohol won't help and "dry gas" is just gas with alcohol, which is what causes the problem in the first place.
Best bet is to set the sender while the gas is relatively clean because it's hard to maintain absolutely clean gas in a boat. I like to set it for Empty with a few inches of gas at the bottom- that way, even if it reads E, you should be able to get home. Unless you're at Kentucky Lake and you went all the way upstream and need to get back to the dam near KenLake Marina.
bigmac
08-24-2009, 04:12 PM
Yeah but it would be nice if the surface area of the strainer was larger than the possible surface area of the impeller vanes.
According to my rough calculations, that would require a strainer with the diameter of 86.0001 millimeters.
According to my rough calculations, that would require a strainer with the diameter of 86.0001 millimeters.
I don't see a problem with that and if I ran a boat in weedy water, I would install a separate strainer and keep a spare impeller/gasket in the boat.
We'll get these to be trouble-free if it kills us!
jchance
08-30-2009, 08:37 PM
OK--here is the lowdown. Made the 2 hour trip back to lake and removed the cover and impeller. It looked like new! Looked closer at the pump and I just did not look right. It looked like it was out too far from the crank. I grabbed the pump and found the entire thing loose and free from the bearings!! The entire rear seal to the pump is destroyed and the entire unit will probably require replacement. I am not familiar with this repair. Here are my questions:
1--I looked at the shaft and I have a set of bearings and what looks like part of a metal seal that is worn out still on the splined shaft. How do I get it off or do I need to??
2--I looked online at the replacement pump from SkiDim (Indmar 68-5020). It looks similar to my pump, but I did not see a bolt-on bracket on my pump like the photo at the SkiDim website. Is mine really just bolted to the crank by 3 bolts? If so, I guess that I could not see them since it is a V-drive and I did not get a mirror out to see in the hole! That would make the replacement MUCH simpler.
3--There were 2 options for the replacement pump: a OEM version and a higher price Sherwood version. Is on any better than the other?
Thanks for everyone's help and I can send a photo of what I am working with if anyone PMs me. I don't know how to attach photos to these posts.
mtajpa
08-30-2009, 09:30 PM
Is it possible that the brass part of the impeller has spun from the rubber part? I have heard this is possible. This picture was from a different post. If your impeller has done this the vanes would look fine because the shaft is turning but the impeller is not. The pump is secured with 3 bolts to the crankshaft balancer. The bracket that holds the pump is on the bottom of the pump. Only has a thru bolt allen type I believe. It actually just prevents the pump housing from turning.
jchance
08-30-2009, 09:50 PM
No, the impeller looks like new out of the package. The problem was with the pump sliding off the shaft about 1 inch and the seals getting eaten. The bearing is still on the splined shaft with a piece of whatever is on the pump side of it. I'm thinking that the entire pump assembly will require replacement. The main question is whether or not my engine has the mounting flange on the damper. It is a V-drive and I did not know to look inside the damper to see if there was a flange inside or not. I know that the replacement has a mounting bracket on the shaft?.
No, the impeller looks like new out of the package. The problem was with the pump sliding off the shaft about 1 inch and the seals getting eaten. The bearing is still on the splined shaft with a piece of whatever is on the pump side of it. I'm thinking that the entire pump assembly will require replacement. The main question is whether or not my engine has the mounting flange on the damper. It is a V-drive and I did not know to look inside the damper to see if there was a flange inside or not. I know that the replacement has a mounting bracket on the shaft?.
Read your PM about how the pump mounts.