Rebuilt 150hp runs, but overheats

M

Mik

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Aug 6, 2004
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28
Well, we go the 80 150 hp rebuilt but the problem is that it overheats. We are running with the muffs connected to the water intake (and a garden hose).<br /><br />The water port on the bottom side "pee's", but not like it should. We were very careful to make sure that all gaskets were matches the way that they should be when rebuilding. <br /><br />Any suggestions on where to start?<br /><br />Mik
 
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rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: Rebuilt 150hp runs, but overheats

how old is the water pump? do you have new pressure valve seats and diaphrams? sounds like something got overlooked :) <br /> good luck and keep posting
 
M

Mik

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Re: Rebuilt 150hp runs, but overheats

Well, we checked the impeller, and it's OK, while we had the gearcase off, we connected a garden hose to the water intake and ran it. Water does run through the block, and out the lower pee spout, as it did when we ran it. <br /><br />Withthe hose attached, the water comes out the lower unit (with the gearcase removed) and it also comes out from behind the shroud around the bottom of the engine compartment. Is that normal???<br /> I'v looked at the gasket that goes between the power head and the exhaust port, but that gasket isn't leaking (which is where the water comes up.)<br /><br />I've gone over the rebuild in my head and I know <br />that all the gaskets are installed correctly. <br /><br />What else can I try? Where does the water flow from the copper pipe up to the thru power head?<br /><br />Where is the thermostat?<br /><br />Mik
 
S

Solittle

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Apr 28, 2002
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Re: Rebuilt 150hp runs, but overheats

Mik - Did you replace the water pump and thermostats (notice I said replace not checked)?<br /><br />What temperature are you running?
 
C

Crossflow235

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Sep 18, 2004
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Re: Rebuilt 150hp runs, but overheats

I agree, if the stats and the pump are old replace them. This way everything is new and you will have a base line, as when to replace them in the future.<br /><br />On my motor (V6)the stats are at the top of the motor above the top cylinder. One on each side. If you replace them make sure you get new rubber gaskets for the stats and a whole new valve poppit assembly<br />(rubber gasket plastic stem, and spring).<br /><br />One last thing to check for, did the rubber seal that seals the outlet of the water pump to the copper tube get installed? Is it fit snuggly around copper tube?<br /><br />Not sure if your pump included one (or if it needs one) but its something to check.<br /><br />The last person who replaced the water pump on my moter failed to install this piece. Not sure how much water was reaching powerhead, but every little bit counts. <br /><br />Hope you can get it fixed<br /><br />SRP71
 
M

Mik

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Re: Rebuilt 150hp runs, but overheats

Still haven't figured it out, but we did some more testing. We again connected the garden hose to the water pump outlet tube (copper pipe with gear housing removed) and ran water through the motor with the thermostats and covers removed (engine not runing of course). What we learned was that water comes out of the port side reasonably fast, but about 1/3 /to 1/4 of the amount of water comes out the starboard t-stat housing even with the port side blocked off.<br /><br />T-stats check out OK in hot water.<br /><br />So there appears to be a blockage on the starboard side.<br /><br />The head gaskets are on correctly. There is a tell-tale tab on the top of each side that is correct.<br /><br />I can't find any documentation that tells me what the water flow is through the engine to try to figure out where the blockage (assuming that both sides SHOULD flow the same).<br /><br />Any ideas???<br /><br />We may end up pulling the powerhead off again, but I can remove the head and the exhaust covers (large plate between the cylinder heads) to gain access to those parts, if there's something to be gained there.<br /><br />We're trying to figure out a plan here, how to attack this thing and figure out what's wrong.<br /><br />Mik
 
S

Solittle

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Re: Rebuilt 150hp runs, but overheats

You said "I can't find any documentation that tells me what the water flow is through the engine to try to figure out where the blockage (assuming that both sides SHOULD flow the same).<br /><br />Any ideas???"<br /><br />Yep - Buy the OMC shop manual. It contains a diagram of the water flow.
 
C

Crossflow235

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Sep 18, 2004
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Re: Rebuilt 150hp runs, but overheats

I looked in my manual and couldn't find any info on water flow diagrams. It just briefly explains overall <br />flow sequence.<br /><br />If you dont have any luck with the manualls <br />try checking out another bulletin board I like to Visit. Bass Boat Central Look under the Evinrude board and post your question there also. <br />Between this board and the other someone should be able to help. Both are very imformative and helpfull.<br /><br />Good Luck, SRP71
 
C

chumbucket

Petty Officer 1st Class
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Oct 12, 2001
Messages
320
Re: Rebuilt 150hp runs, but overheats

Did you replace rubber gromment that the plastic poppet valve ride's in . They collapse now and then. Had 48 Evinrude that that $2.00 part was the overheat problem.
 
S

seahorse5

Rear Admiral
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Jan 24, 2002
Messages
4,698
Re: Rebuilt 150hp runs, but overheats

There are 6 rubber water deflectors that fit between the cylinders and the block part #322411. If they are deformed, missing, or damaged, the motor can overheat. Since it was recently rebuilt, were these deflectors removed and not replaced?
 
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rigney

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Sep 20, 2004
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Re: Rebuilt 150hp runs, but overheats

Seahorse is all over it, I would say that a water deflector in the head is dryrotted or missing. Also the strbd head will not spray as much water as the port side. This is normal, because the high side needs more water to cool than the lower side.
 
M

Mik

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Re: Rebuilt 150hp runs, but overheats

We did a lot of checking:<br />1. The rubber grommets on the poppet valves are OK, No leaks. We have removed the t-stats and the poppet valve.<br /><br />2. I looked at the rubber water deflectors in the cylinder walls, they were all in very good condition. I didn't remove them, but there were none that were rotted. It is something that we can check again.<br /><br />3. "Seahorse is all over it,"... I don't understand that reference.<br /><br />But as I mentioned, we'll recheck the water deflectors. It's not that big of a deal to pull the head off. Also, as I mentioned before, we're going to replace the T-stats and the water pump.<br /><br />Thanks for the suggestions.<br /><br />Mik
 
H

Hooty

Rear Admiral
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Oct 2, 2001
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Re: Rebuilt 150hp runs, but overheats

See if this helps.<br /><br />
site1117.jpg
<br /><br />c/6<br />Hooty
 
R

rfischer63

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Joined
Mar 19, 2008
Messages
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Re: Rebuilt 150hp runs, but overheats

I also have a 150hp crossflow that runs hot on the strbrd side at low rpm,
with stat cover off no water, comes out, bring rpms up and some water
flows.?
 
C

cdoliver

Petty Officer 1st Class
Joined
Mar 18, 2008
Messages
211
Re: Rebuilt 150hp runs, but overheats

also, a muff can't flow the same amount of water as actually being in the water can.
 
R

rfischer63

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Joined
Mar 19, 2008
Messages
6
Re: Rebuilt 150hp runs, but overheats

I also have a 150hp crossflow that runs hot on the strbrd side at low rpm,
with stat cover off no water, comes out, bring rpms up and some water
flows.?
 
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