2000 Johnson 50 hp J50PLSSM crank rod issue?

[slx12001]

I'm rebuilding a customers 2000 johnson J50PLSSM. The lower piston and cylinder look like they didnt get any oil. Upon inspection when pulling the pistons out I noticed that the pistons were oriented correctly on the rods but I believe that one of the rods were installed at some point with one backwards. I checked my service manual without any help. Historically in general the rods go in so that you can read the part number up. These rods have another number on the other side that is not an oem part number but I believe a casting number possibly? Anyway The rods have the typical 2 indicator dots on the rod and cap. Please look at the pictures. The piston that failed had the rod installed so you could read the omc part number up. The one that looks great and had 145+ psi has the omc part number facing down. I really wanted to blame this failure on the vro system but the top cylinder and piston look great. The seals are all great as well. Carbs were clean and look good as well. Hmm. What does this all mean. lol Any help with the correct orientation of the con rod will get me started. Thanks for any insite here.

 

[Faztbullet]

It don't matter about the numbers direction it's the oiler hole for wrist pin that faces up.

 

[slx12001]

Thanks for the reply. This rod does not have a hole in the rod on one side. The hole does not ever face up installed where it's located. I was thinking place the hole side starboard side of the block or intake side. Either way the rods were installed opposite sides. Manual states up as well but not possible with these rods.

 

[daselbee]

All the oil that a cylinder needs comes from the mixed fuel. You know that. The fact that the rod is reversed will not stop the oil from the fuel from getting to the cylinder walls. The only thing that MIGHT happen from the reversed rod is maybe a wrist pin bearing failure, because that hole allows oil down in there to the bearing.
That cylinder ran lean in my opinion. Look at the carb again carefully. The high speed circuit / jets/ nozzle area. Double check the venturi throat to make sure the plastic is not crazed. I saw one carb throat that was crazed from using ether based starting fluid. The crazing causes airflow disruption, and the carb runs lean.

 

[daselbee]

Just thought I would look the parts up on this...and I find that you do not have plastic carbs. Sorry for assuming. However.....still think it ran lean and you must find out why, or ir will happen again. Carbs first.

 

[slx12001]

Thanks for the replies. My only concern is the rod going in backwards. Most engines spec the rod in a specific direction. The oiling of the main or piston pin follows. Carbs look great no blockages. When vro fails generally in a twin it's the top piston that sticks first. This was the bottom. I have searched high and low for exact oem spec for rod direction for this engine. No exact spec. I will position the piston pin oiler on the intake side as it makes sense. Not much oiling on the exhaust side

 

[slx12001]

If anyone comes across this in the future found an oem evinrude service manual and it stated rod placement does not matter so oiler can be on either side.

 

[cfauvel]

Thanks for the replies. My only concern is the rod going in backwards. Most engines spec the rod in a specific direction. The oiling of the main or piston pin follows. Carbs look great no blockages. When vro fails generally in a twin it's the top piston that sticks first. This was the bottom. I have searched high and low for exact oem spec for rod direction for this engine. No exact spec. I will position the piston pin oiler on the intake side as it makes sense. Not much oiling on the exhaust side

Curious to "when vro fails generally...."

what exactly are you finding failing? The oil piston is directly linked to the fuel diaphragm and air motor. If the fuel/air side is pumping, then the oil side is too.

a few things that I came up with that could lead one to label a "vro failure" are

that the oil reservoir has water in it, thus sucking water rather than oil. (the no-oil alarm would NOT sound)
the oil reservoir's sock is gummed up with a jelly like substance, thus sucking and getting nothing (the no-oil alarm would sound)
the oil line has a kink, thus sucking and getting nothing or a little (the no-oil alarm MAY or MAYNOT sound, depending on the amount of fluid)

granted if the low-oil alarm and the no-oil are malfunctioning, then indeed if you have no oil left in reservoir you will toast the engine.

Those two items need to be checked periodically.. If your tach isn't working because of a faulty regulator, your no-oil alarm WILL NOT sound.

I guess going pre-mix is a safer route if you don't care about a functioning tach et al.

 

[flyingscott]

Thanks for the replies. My only concern is the rod going in backwards. Most engines spec the rod in a specific direction. The oiling of the main or piston pin follows. Carbs look great no blockages. When vro fails generally in a twin it's the top piston that sticks first. This was the bottom. I have searched high and low for exact oem spec for rod direction for this engine. No exact spec. I will position the piston pin oiler on the intake side as it makes sense. Not much oiling on the exhaust side

If the VRO fails you are usually cutting the pistons out of the hole. I have seen a few complete failures from a VRO and those were early ones and they are not pretty.