1966 9.5 Johnson Cooling System

[Brian Robertson]

A 1966 9.5 Johnson was in the house when we bought the house. We don't know how long it has been there or whether it has had good service. The water pump seems to work but not all the time. Water comes out of the telltale at a pretty good rate for a while and then it stops. Could this be due to a thermostat. I bought the service manual Johnson put out but it is of little use. I have parts to fix the water pump but not sure about the thermostat? I have read many posts on this board about replacing the impeller and have tried to drop the lower unit by removing 4 bolts and the shift linkage but it doesn't seem to want to seperate. Could there be something else holding it or could it just be old age? Engine runs well other than that. If there is a thermostat can anyone tell me how to order one by mail order - 800 or email? We are stuck on a small island off Puerto Rico and can't buy much in the way of parts here - certainly not for something that old. Thanks for any tips

 

[maked]

Re: 1966 9.5 Johnson Cooling System

the thermostat, is generally not critical on some of the older outboards, providing the water isnt freezing which i doubt in puerto rico. take it out if you are wondering. A quick test to see if it is functioning is to drop it into a glass of very cold water, then take it out and dropp it into a glass of boiling water( or hold it in the steam coming out of the kettle) you should hear/see it click if it does its working. As for the lowerleg, most outboards overtime seize up a little where the propshaft enters the end of the crankshaft, a little gentle persuasion may be needed in the form of a gentle tapping with a rubber mallet, downwards on the cavitation plate can be helpful as the weight of the leg serves to help you out. Dont do it to hard, if you get any movement place two flat screwdrivers on either side between the parts and you should be able to lever it off. Always be gentle with the aliminium casings!!

 

[slow_boat]

Re: 1966 9.5 Johnson Cooling System

Same problem w/69 9.5. It is definately an issue of the driveshaft being corroded onto the crankshaft. Drain ALL water from the leg. Turn unit upside down with leg straight up. Buy can of PB Blaster...you may have to get it from the internet if not sold there. Spray 1/2 can of blaster through the seperated lower unit opening, trying to get it to run straight down the driveshaft to the bottom of the power head. Let it sit several days, coming out each day to wiggle, jiggle, tap, & pull on the lower unit. After several days you should be able to work it free. Note: WD 40 is NO good for a job like this...get the blaster...it is worth your time. Be patient, it will come off with no damage if you are. Also...Do Not run your engine if no water is pumping...you WILL ruin your engine in short order...sounds as if the impeller is worn out on your engine. FWIW, there are numerous posts on this board regarding stuck lower units & you might want to do a search to read other's experiences with this issue.

 

[Brian Robertson]

Re: 1966 9.5 Johnson Cooling System

Thanks for the tips and suggestions. I will try them. I am not sure about the thermostat thing and where it might be but I can probably figure it out. It seems the water cuts out as the engine heats up. The flow seems good when it is first started but after a while it quits. Does the thermostat doing anything like route more water through the exhaust when it gets hot? I doesn't make sense to me that there would be less water when the engine gets hot - have to figure it is the pump and not the thermostat though I will try to check the thermostat out. It may take a while to get the PB Blaster here but it is on my list of things for the next time I go to PR. Any ideas on where I might get the thermostat online if it turns out I need one? OMC does not show dealers here though I know they are here somewhere I can't seem to locate them. OMC search doesn't show anything for PR. Also, I have seen some mechanics us some sort of tachometer that they put up against the engine and somehow - by vibration - it can tell the RPM's. Does anyone know about these or where someone might find one. Thanks

 

[slow_boat]

Re: 1966 9.5 Johnson Cooling System

Thermostat is mounted just above top cylinder (#1) and has 3 bolts holding its cover to the block. Almost always, if the t-stat fails, it is in the OPEN position. When an impeller is worn out or weak, it may pump water upon startup & @ idle but NOT at speed.

 

[Brian Robertson]

Re: 1966 9.5 Johnson Cooling System

As it turns out there is a connection joining the upper shifting linkage to the lower shifing linkage inside the housing right where the water pump is - you have to pry the housing far enough apart to get a 3/8 socket in there to loosen the clamp - the rod has a sort of knurl (not sure of technical term) to hold it in the clamp so you have to pry the clamp a little to get it to pull out - loosening the upper linkage really do anything so I opened the lower unit and disconnected the linkage there to get a little more play - the linkage rods will not go down from the top or up from the bottom to get them out - the only way is to loosen that clamp and then pull the linkage up from the top or down from the bottom - there are other factors involved but the point is you need to disconnect the linkage inside the housing right by the water pump or you cannot completely seperate the housing to get to the pump - thanks for all the other tips..

 

[slow_boat]

Re: 1966 9.5 Johnson Cooling System

Glad you got it out. From your first post it appeared you had already removed the shift linkage retainer you mentioned in your last post. I believe that is why we assumed you had a frozen shaft.