Blew a water pump hose on a 165 mercruser l-6

[Sawz]

Got a old boat I bought last summer that had a cracked block up and running this spring. Had to put another 165 straight 6 engine in it that I had kicking around. Had it professionally installed. and they put a new impeller in it while the drive was off. New gimbal etc etc. Had it on muffs a few times while I tuned it up and rebuilt the carb. It would come up to temp and stay even . Out on the lake tonight I ran it up to WOT after it warmed up. stayed ok for a while I noticed the temp ran up to around 190 Hotter than sitting in the drive way Idling. Had it going for a bout 15 minutes and when I looked down I noticed it was pretty hot over 200 then it went down quickly I figured a stuck Thermostat I turned around and headed back when it ran up again and then blew the hose and split it wide open. Steam, water and the whole mess. I was still out a 1/2 mile from dock. Had to have my son hold the hose together, lol and turn the bilge pump on and make tracks. I watched the temp thinking it might still be stuck but it never got hot again, maybe stuck open now? son said the water got warm but not hot. Got back ok besides son all wet, and loaded it up .

My guess is the thermostat stuck shut then blew the hose, would that be a good guess? Also I noticed on this engine after doing a search for hoses that there is some people doing a modification reversing the flow in the manifold is this a good thing to do?

Also Im having a bit of trouble finding the molded hose between the pump and thermostat housing. is it ok to use one of those " universal hoses on this application, or keep digging?

Thanks for your knowledge in advance

 

[Pete104]

Re: Blew a water pump hose on a 165 mercruser l-6

If you are describing this right, the hose you want ( that runs along side the carb) is 3/4" heater hose! That engine has got 2 molded hoses on it. Circ pump to stat hsg (2" both ends) & stat hsg to exhaust manifold (1" both ends)!

 

[mike165]

Re: Blew a water pump hose on a 165 mercruser l-6

Same thing happened with my 165 two years ago,was a partly blocked riser not letting enough water flow thru the motor,it got hot and blew the hose,on the pump/thermo get the right one the bend is tight

 

[Sawz]

Re: Blew a water pump hose on a 165 mercruser l-6

If you are describing this right, the hose you want ( that runs along side the carb) is 3/4" heater hose! That engine has got 2 molded hoses on it. Circ pump to stat hsg (2" both ends) & stat hsg to exhaust manifold (1" both ends)!

it was the circ pump /thermostat hose the 2" one

 

[Sawz]

Re: Blew a water pump hose on a 165 mercruser l-6

What makes me think it was the thermostat is that it would cool off after reaching hotter than normal

 

[ziggy]

Re: Blew a water pump hose on a 165 mercruser l-6

Also Im having a bit of trouble finding the molded hose between the pump and thermostat housing

item #45 from here.

What makes me think it was the thermostat is that it would cool off after reaching hotter than normal

ya could try testing the t stat in a pan of water w/ a thermometer in the water. note temp when it starts to open and what temp is when it is full open. see if the t stat starts to close as the water cools down.. or.. replace the t stat, they're not to expensive and call it pm.
i believe you should have a 143*F t stat assuming ya got raw water cooled system. t stat should start to open and 143 and become full open at 163*F. or +20*F of specified value of the t stat.

 

[achris]

Re: Blew a water pump hose on a 165 mercruser l-6

it was the circ pump /thermostat hose the 2" one

Same thing happened with my 165 two years ago,was a partly blocked riser not letting enough water flow thru the motor,it got hot and blew the hose,on the pump/thermo get the right one the bend is tight

Correct-a-mondo.... Very common...

Think about your stuck thermostat theory for a minute.... How does the engine normally reach operating temperature? By the thermostat being closed until the water in the engine reaches the thermostat opening temperature.

The hose you're looking for is 32-96879, and is still a current part, so a Merc dealer will be able to get it for you, and it's only about $35.. and you're going to new a new exhaust elbow, part# -76351A04.

Manifold water reversal... Service bulletin 83-19 (http://www.marinepartsman.com/Mercur...1983/EN_19.PDF). Do a search here and you find heaps of posts. I think it was Fishermark who posted up photos...

Chris.....
Found the post for you... http://forums.iboats.com/showthread.php?t=261607&p=1750654&viewfull=1#post1750654