rebuilt johnson power head

[Salty Dawg]

Before I head down this road, I would like some pros & cons from you guys "that been there" concerning rebuilt large bore Johnson power heads from iboats list of rebuilders. Since I am green at this, all suggestions are welcome.

 

[Dhadley]

Re: rebuilt johnson power head

The absolute number 1 thing is to determine what caused the damage that requires a replacement or a rebuild. A damaged piston is not the cause -- its an effect. Fix the cause. <br /><br />Good luck!

 

[willxuout2]

Re: rebuilt johnson power head

Salty Dawg:<br /><br />Dhadley is RIGHT! Powerheads just don't fail for no reason. There is always a contributing factor. My powerhead failed due to carburation. When I had a reman ph installed everything else was checked out or rebuilt. Always rebuild and replace the carbs, fuel lines, recirc valves and all associated hoses. The reman ph will last a long time if you maintain the motor. Always use fresh fuel and oil. I premix so i've taken the VRO out of the equation as far as the oil is concerned. However, I would replace the VRO pump when you rebuild whether you premix or not.<br /><br />Good Luck!

 

[rodbolt]

Re: rebuilt johnson power head

hello<br /> the other major concern with a big bore jonnyrude is the condition of the aluminium around the cylinder sleeve. it tends to disapear in salt water .<br /> other than that gor for it<br /> good luck and keep posting

 

[Dhadley]

Re: rebuilt johnson power head

It also depends on which family of motors he's talking about as being "big bore". We have the "big bore" 3 cylinders, "big bore" V6 crossflow and "big bore" V4, V6 and V8 loopers. The 160 ci crossflow is fairly slim on aluminum compared to others. <br /><br />Oh and the "bigger than big bore" 3.3 liter block.

 

[Salty Dawg]

Re: rebuilt johnson power head

Thanks for the various info. But let me back up and restate my problem. The # 2 cylinder of this 175 HP, 6 cylinder looper connecting rod went through the side of the block, taking a large section of the block with it. The engine was cranked cold and my have been over reved. Rather than look for and empty block and rebuild with some of the existing parts and my lack of experience. I belive I would be better off with an after market rebuilt power head and was hoping some of you guys had faced this problem and could direcly be toward the right remanufactuer.

 

[Dhadley]

Re: rebuilt johnson power head

Before we go any further, lets get the model number and see what you have. We dont really refer to a 175 looper as a "big bore" or "small bore". 175 loopers are a 60 degree motor and have always been the same bore. <br /><br />However, a 175 crossflow can be what we refer to as a "big bore". Its an older motor and a crossflow. These are two totally diferent motors.<br /><br />Regardless of which it is, you need to find out what happened to cause the rod to break. In most cases the piston sticks and then the rod breaks. You will need to find out what caused the piston to stick, if this is the case. It could be from carbs or ignition components which you will transfer to the new/rebuilt powerhead. You dont want a repeat performance.

 

[Salty Dawg]

Re: rebuilt johnson power head

Sorry about the wrong engine information. The engine is a 1996 175 HP 60 degree V6 (loop charged). My main concern is what manufacturer should I purchase the rebuilt power head from and then try figure out what went wrong and with the original engine. Thanks