help help help overheating Mecrusier

karayj

Chief Petty Officer
Joined
Aug 4, 2002
Messages
433
When I did my first two impellers on my own, I made sure I was watching a YouTube video and I looked at the direction the fins were pointing. I think it’s a clockwise scenario that the fins have to point in a clockwise angle.
 

Scott06

Vice Admiral
Joined
Apr 20, 2014
Messages
5,837
That’s a great tip, but wait what about the guy that doesn’t have $2000 to drop on maintenance what does that guy do?
not by a boat... Also thats not $2 k worth of parts. Unfortunately if you dont spin your own wrenches you need a checkbook
 

havoc_squad

Senior Chief Petty Officer
Joined
Mar 5, 2011
Messages
714
That’s a great tip, but wait what about the guy that doesn’t have $2000 to drop on maintenance what does that guy do?
Then one has chosen the wrong activity/hobby if they can't afford it, don't buy a boat if you can't pay to get the work done.

Whether that be the owner performing the repairs or a service shop, you pay to get it fixed or you sell the boat for what you can or not buy a boat at all.
 

karayj

Chief Petty Officer
Joined
Aug 4, 2002
Messages
433
Then one has chosen the wrong activity/hobby if they can't afford it, don't buy a boat if you can't pay to get the work done.

Whether that be the owner performing the repairs or a service shop, you pay to get it fixed or you sell the boat for what you can or not buy a boat at all.
Sorry I disagree. LEARN how to fix the basic thing. I see coworker pay 600.00 for a 30 brake job I have seen a person pay 1500 to install a 1 hours alternator in a car !!! My point is these shops can realy SCREW you over. So it is best to come here and LEARN not run and pay someone. I rebuilt my top end in hours for 225.00 is parts. Shop wanted 1,800. I paid 1,500 for the boat. Boating should not be a thing only rich people can do !
 

stresspoint

Lieutenant Junior Grade
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Sep 19, 2022
Messages
1,028
the best things you can do if you want to own a boat on a limited budget .
#1 , have a workshop full of tools (or unlimited access to one).
#2 , have a friend or relative that is mechanically inclined that can come and help you with just a phone call.
#3 ,have plenty of time to fix stuff that breaks ,to do regular maintenance, spend time chasing parts.
#4 , have a good income , well, enough to feed that extra mouth in the family.IE; maintenance ,parts , fuel , service items.
#5 , learn how to buy good serviceable used used parts.
#6 , and most important : , don't be afraid to get cut up arms , squeezing into places a contortionist would be proud of you.
#7 , remember to do the job right the first time so as you don't have to fix what you just fixed after a few outings , or worst still whilst you are using your boat.

i am sure this list could go on forever , but point being , these things are expensive time consuming fun toys no matter how you look at it .
 
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Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,950
boating is more expensive than auto racing and just a tiny bit less expensive than owning airplanes or racing horses.

the only way to boat on a budget is to do the work yourself. and that is the list just above and a few more items:

#8 have an understanding wife/girlfriend/significant other
#9 be too poor to buy cheap parts twice or more. good parts are worth their price.
#10 above all else, make sure the boat is safe and will get you home
 

havoc_squad

Senior Chief Petty Officer
Joined
Mar 5, 2011
Messages
714
Sorry I disagree. LEARN how to fix the basic thing. I see coworker pay 600.00 for a 30 brake job I have seen a person pay 1500 to install a 1 hours alternator in a car !!! My point is these shops can realy SCREW you over. So it is best to come here and LEARN not run and pay someone. I rebuilt my top end in hours for 225.00 is parts. Shop wanted 1,800. I paid 1,500 for the boat. Boating should not be a thing only rich people can do !

This sounds like knee jerk reacting to me here.

Just because you might think a service shop charging about $1000 to $1200 (parts & labor) for a complete bellows replacement is a rip off doesn't have much weight. They can go and pay someone else to get a second opinion, or do some research on the correct shop rate hours are and market shop rate in area, or research if this is something they can do themselves.

Depending on where you live, that is a fair price given the parts cost and shop labor of about 6 hours.

Regardless, as I've said before. You pay to play in the powered boating hobby or you sell and get out of it if you can't afford it.

I'm just as much of a DIY budgeter as a lot of those on this forum and live by the fact stated above.
 

spomey

Seaman Apprentice
Joined
May 10, 2023
Messages
36
Start by seeing if you get the proper water flow up from the drive. First attachment has flow test should get 3-4 qts in 15 seconds up up to thermostat housing. Is the hose that comes from transom housing up to thermostat housing.
second photo is your cooling system diagram. Shows water flow. If you have right amount of water coming to housing look for blockages. If not enough water check ps cooler on flywheel cover. it can get clogged.

did you use a quality impeller ? Oem is best for impellers . Did you forget the key when installing impeller?

water pump on block is a circ pump circs cold water from thermohousing into block up and out heads back to thermostat when thermo is open.
two small lines to manifolds need to pass water at all times to cool exhaust system regardless of what thermostat is doing .
I bought a merc impeller kit and installed again, no water flow. So I removed the lower drive unit again and I put a garden hose at the thermostat housing Line coming from the impeller. i got full flow in that direction out the pick up tube hole. when i tried going from the pick up tube towards the engine I could not get any flow at all. that seems so strange to me. any ideas?
 

dave8311

Seaman
Joined
Jun 6, 2022
Messages
73
Sounds like old impeller vanes in the coolers blocking the flow. Not sure how it could be one direction only, but there it is.
 

Scott06

Vice Admiral
Joined
Apr 20, 2014
Messages
5,837
I bought a merc impeller kit and installed again, no water flow. So I removed the lower drive unit again and I put a garden hose at the thermostat housing Line coming from the impeller. i got full flow in that direction out the pick up tube hole. when i tried going from the pick up tube towards the engine I could not get any flow at all. that seems so strange to me. any ideas?
Take the hose off the inlet to the power steering cooler I bet you will find debris on the outdrive side of the cooler. When you back flush to drive they get lifted off the face of the cooler which is a shell and tube heat exchanger. When you go forward it gets pushed against the face again blocking flow

These coolers have very small holes in the tubes that the water goes through can get plugged
 

bradiggy

Cadet
Joined
May 9, 2023
Messages
13
Did you happen to check for / replace the two o-rings on the inside of the tube that connects directly to the impeller housing and slides into the upper drive when you reassemble? I just replaced my impeller a few days ago for the first time and my first thought when installing was if those O-rings are missing, you'll get zero pressure in the system.

And I think you mentioned it earlier, but you did get the keyed shim piece that aligns with the shaft that actually causes the impeller to spin right?
 

Simoniz

Petty Officer 1st Class
Joined
Dec 30, 2007
Messages
241

this is part one of two. This guy is s legit mechanic who used to be a moderator on this forum should have link to part 2 when u watch this
Interesting that he says that drive hasn't been apart for 7 years, and that he would replace the impeller if it only had 2 or 3 years use on it. I thought impellers were recommended to be changed every 2 years.

Despite that, I have had my boat (Bayliner, Mercruiser 3.0l Alpha 1 Gen 2) put in the water by crane and it now seems to have a low speed overheat, with minimal water flow at 800rpm idle speed. I thought the impeller was max 2 years old, but on checking it was last replaced in 2018. Its an OEM impellor and I find it difficult to imagine it had disintegrated, as the water flow is fine at 1200 rpm and above.
 

spomey

Seaman Apprentice
Joined
May 10, 2023
Messages
36
When I did my first two impellers on my own, I made sure I was watching a YouTube video and I looked at the direction the fins were pointing. I think it’s a clockwise scenario that the fins have to point in a clockwise angle.
Thank you to all for ideas and things to try. it turns out i took the supply path apart and checked each pice for flow until i found what i thought was the culprit. the fuel heat exchanger, so I removed that (not the worst thing I have done but tight cramped and head to work "blind" got it out....nope! there is basically no way that thing could get clogged. turns out the prior owner assembled the check valve between the fuel cooler and the thermostat backwards. reassembled and now I get flow, but the engine is not getting fuel. another problem....but I think I left the sensor in the out drive unplugged that may be a ground or part of a circuit to allow the fuel pump to run.

thank you all....its always the simple things.
 

Scott06

Vice Admiral
Joined
Apr 20, 2014
Messages
5,837
....its always the simple things.
If I had a dime for every time I said that at work trying to figure out a mechanical or process issue.... everyone tries to split the atom before checking the basics.

The cool fuel looks like a MF to get at unless you like hanging upside down.

At least now you know how the system works.
 
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