Help!! Over heating only in water

OldEngineer said:
Aaron,
I apologize! I did not read your original post completely. You are a Master Auto Mech! I had a thought ... (they still happen occasionally *grin*) if you have one of those new-fangled infrared heat sensors, try aiming it at each side of the engine. From what you described about the uneven exhaust water flows, perhaps one side of the engine is hotter than the other, which would point to a possible partial blockage of the water channels in that side of the engine. It's a start at least. Wadda ya think?

Regards,

Al
Click to expand...

Well all your right that's a good start considering.. I broke my laser temp tool but I got a few buds I can borrow one from ? Should the out flow be the same on both exhaust the small port sides holes..
Yep master auto tech but this outdrive and funky boat water cooled everything really got me hugging my mercruiser service books hard!! Glad I got them.. I can handle building engines and electrical all day but I'm learning these boats fast I tell ya



Sent from my iPhone using Tapatalk
 
Your impeller is working, yes, but the question is "how well is it working". In one of your first posts you said the housing looked "shabby"... see my response about that. I think that's the first place to start.

Generally, a "V" engine will produce approximately equal amounts of water coming out of the exhaust ports. If the boat is sitting uneven (listing), though, that could affect it. The exhaust manifolds empty into a Y-pipe where both sides are combined. The water then takes the path of least resistance out/through the transom.

However, that is nowhere near enough water coming out of your exhaust ports. It also does not look like enough water coming out at the t-stat housing. It does appear that the muffs weren't completely covering the intake ports, though. But if they were, it's seriously low on water. And we're back to the most common thing to check... impeller or impeller housing. It takes 10 minutes to drop the foot and another 10 to check the housing. Start there - replace the housing (get a kit) if there is ANY doubt.

I was going to mention another easy test to see if the engine truly is overheating, but it's likely a moot point given the lack of water flow and the "shabby" housing. There's also a test for the proper amount of water flow coming to the t-stat housing, but I really don't think it's necessary - however that's in your service manual if you want to look it up just for the fun of it. It basically involves measuring how much water actually comes out over a period of time and at a set RPM. I don't have the book in front of me, but it's something like 15 seconds at 1,000 or so RPMs. The leg MUST be in the water for this test. Should be somewhere around 3 or 4 qts - depending on drive ratio.
 
Last edited:
Lazy Daze said:
Your impeller is working, yes, but the question is "how well is it working". In one of your first posts you said the housing looked "shabby"... see my response about that. I think that's the first place to start.

Generally, a "V" engine will produce approximately equal amounts of water coming out of the exhaust ports. If the boat is sitting uneven (listing), though, that could affect it. The exhaust manifolds empty into a Y-pipe where both sides are combined. The water then takes the path of least resistance out/through the transom.

However, that is nowhere near enough water coming out of your exhaust ports. It also does not look like enough water coming out at the t-stat housing. It does appear that the muffs weren't completely covering the intake ports, though. But if they were, it's seriously low on water. And we're back to the most common thing to check... impeller or impeller housing. It takes 10 minutes to drop the foot and another 10 to check the housing. Start there - replace the housing (get a kit) if there is ANY doubt.

I was going to mention another easy test to see if the engine truly is overheating, but it's likely a moot point given the lack of water flow and the "shabby" housing. There's also a test for the proper amount of water flow coming to the t-stat housing, but I really don't think it's necessary - however that's in your service manual if you want to look it up just for the fun of it. It basically involves measuring how much water actually comes out over a period of time and at a set RPM. I don't have the book in front of me, but it's something like 15 seconds at 1,000 or so RPMs. The leg MUST be in the water for this test. Should be somewhere around 3 or 4 qts - depending on drive ratio.
Click to expand...

Great info man I'm gonna do the impeller kit tomorrow what way do the canes curve and the boat is a lil tilted on the trailer I'll let you guys know when I change the impeller


Sent from my iPhone using Tapatalk
 
you can install the impeller a few ways. Install it on the driveshaft first , lower the upper cover while turning the shaft clockwise. Second method it to run it under hot water, insert into the upper housing turning the impeller CCW.
The reason you dont overheat on a hose is because your forcing the water thru the pump, not pumping it per se.
 
I hold the cup in my left hand, impeller in my right, and turn the impeller CCW as I push it in. You can use some lube to get it in easier - but it's best not to use petroleum products on rubber items. Use some dishwashing soap, silicone spray, etc. You can also run a ziptie around the vanes to compress them.

Aaron, can you do me a favor? I'm having a hard time following some of your posts due to the lack of punctuation. I know it's the way you kids communicate now a days, but I'm still a little old school. :smt001
 
Bt Doctur said:
you can install the impeller a few ways. Install it on the driveshaft first , lower the upper cover while turning the shaft clockwise. Second method it to run it under hot water, insert into the upper housing turning the impeller CCW.
The reason you dont overheat on a hose is because your forcing the water thru the pump, not pumping it per se.
Click to expand...

I Like that ideal about the impeller thanx doc..


Sent from my iPhone using Tapatalk
 
Lazy Daze said:
I hold the cup in my left hand, impeller in my right, and turn the impeller CCW as I push it in. You can use some lube to get it in easier - but it's best not to use petroleum products on rubber items. Use some dishwashing soap, silicone spray, etc. You can also run a ziptie around the vanes to compress them.

Aaron, can you do me a favor? I'm having a hard time following some of your posts due to the lack of punctuation. I know it's the way you kids communicate now a days, but I'm still a little old school. :smt001
Click to expand...

Sure daze what do I need to do? So you can follow maybe it's the mobile app I'm using


Sent from my iPhone using Tapatalk
 
Have you checked that the key that locks the impeller to the shaft is in place? Wouldn't be the first time that has been overlooked!
 
You've made some contradictory statements here....Post 20 said you put a new pump on it 4 months ago...post 23 said your going to put a new pump on it????
 
scoflaw said:
You've made some contradictory statements here....Post 20 said you put a new pump on it 4 months ago...post 23 said your going to put a new pump on it????
Click to expand...

New circulation pump the one on the engine....yes I have also replace the impeller pump twice in the last three months as well but with the impeller I'm not sure if I done it right the first time and with this being my first boat I may have ran it too long and burned up the impeller before connect in the water after ...I can't remember


Sent from my iPhone using Tapatalk
 
tykes said:
Have you checked that the key that locks the impeller to the shaft is in place? Wouldn't be the first time that has been overlooked!
Click to expand...

Yes the key is in... Like I said it pumps I just don't think it's enough and was only running hot in the river at idle.. Sometimes if I would gas it a little it would cool down a little bit


Sent from my iPhone using Tapatalk
 
You are going down the same road I did about 7 years ago. Changed the circulating pump new water pump but would not over heat on muffs bUT would in the water at low rpm but not higher rpm. Took 2 years to discover a flapper had fallen down into the Y pipe. On the muffs enough pressure on water system to keep the engine cool. Pull the hose off the riser and have a look bet you find a flapper missing.

Ken
 
Iprof said:
You are going down the same road I did about 7 years ago. Changed the circulating pump new water pump but would not over heat on muffs bUT would in the water at low rpm but not higher rpm. Took 2 years to discover a flapper had fallen down into the Y pipe. On the muffs enough pressure on water system to keep the engine cool. Pull the hose off the riser and have a look bet you find a flapper missing.

Ken
Click to expand...

Ken funny thing I took the riser off months ago just to change the hose and there was no flapper but at that time I thought there was nothing supposed to be there 1st inboard boat as I mentioned before the same side riser hose blew off twice .. So you just might be right it would also explain while it's such low water coming out of the left exhaust hole port armed with this information I'm ready to go outside and pull the right side off and look but this storm well you know so what's the fix and once I remove the flapper if it is there can I run with out it or do I need to replace it??


Sent from my iPhone using Tapatalk
 
Iprof said:
You are going down the same road I did about 7 years ago. Changed the circulating pump new water pump but would not over heat on muffs bUT would in the water at low rpm but not higher rpm. Took 2 years to discover a flapper had fallen down into the Y pipe. On the muffs enough pressure on water system to keep the engine cool. Pull the hose off the riser and have a look bet you find a flapper missing.

Ken
Click to expand...

Hey Ken I just read about the different y pipes there is a 3 piece older style and a one piece newer style and that the 3 piece which I have has the flapper located in the bottom not the top which would explain why I don't see it ....dang but don't mean it's not damaged tho.. This is so frustrating


Sent from my iPhone using Tapatalk
 
While an exhaust flapper could be the cause of lack of water coming out and of overheating, that does not explain the lack of water going IN. Check the hose that goes from the bell housing up to the transom assembly and see if it's kinked. If it was replaced and someone didn't cut it to the exact length it needs to be it WILL kink. Also check to make sure the tube going out of the top of the pump housing to the upper unit has both of it's rubber seals intact. where they are supposed to be, and the right way around. It is possible that at some time an impeller came apart and bits of it are clogging things up (been there done that). Be careful if you try to pull the piece in the upper unit that the water tube goes into. A lot of times the bolts will simply snap off, then it's time for a new upper housing.
 
Forgot to ask, you did put the little rubber seal around the shaft on top of the impeller housing right? That has to be there or water will simply come out around the shaft.
 
LiquidWrench said:
While an exhaust flapper could be the cause of lack of water coming out and of overheating, that does not explain the lack of water going IN. Check the hose that goes from the bell housing up to the transom assembly and see if it's kinked. If it was replaced and someone didn't cut it to the exact length it needs to be it WILL kink. Also check to make sure the tube going out of the top of the pump housing to the upper unit has both of it's rubber seals intact. where they are supposed to be, and the right way around. It is possible that at some time an impeller came apart and bits of it are clogging things up (been there done that). Be careful if you try to pull the piece in the upper unit that the water tube goes into. A lot of times the bolts will simply snap off, then it's time for a new upper housing.
Click to expand...

Hey what seals are you referring to in the pump housing ? 2 seals you say


Sent from my iPhone using Tapatalk
 
You must log in or register to reply here.

Forum statistics

Threads
113,253
Messages
1,429,371
Members
61,132
Latest member
MinecraftRu1Swilm
Back
Top