1990 Johnson 70 VRO

[ShawnQ]

I am thinking about purchasing a boat with a 70hp Johnson, 1990 model, Tilt/Trim, VRO.<br /><br />I was looking at it yesterday, and I had the dealer fire it up. The boat has a water pressure gauge on it, and it was only reading in the 2-3psi range, and I realized that was low. I also noticed an excessive stream of water coming out of the two ports just below the engine fairing.<br />I asked the mechanic at the dealer about it (kind of hiding the fact that it was about the dealer's boat), and he said most boats that have the water coming out of those ports have the thermostats removed, and it generally has no ill effects on older engines. He said that because we are so far south, the previous owner may have removed them to get better cooling 100% of the time. He also said that this would lower the water PSI.<br /><br />Is he feeding me a line of BS, or is this true?<br /><br />The engine ran great, fired right up, idled smooth, makes good compression, and everything looks clean other then a little bit of salt corrosion (which is to be expected.)<br /><br />Any advice is appreciated, the boat/motor/trailer seemed like a steal at the asking price.<br /><br />Thanks!<br />Shawn

 

[OBJ]

Re: 1990 Johnson 70 VRO

Hi Shawn...<br /><br />Yeah it would lower the water pressure cause ya' got a straight shot thru the engine. Don't know about people removing the t-stats though down south as I live up here in Ohio. Maybe true, dunno. But I do know that if ya don't have t-stats, then you may run with an engine below rated temp. This does no good for burning fuel. Maybe one of the other guys with "Southerly" experience can shed some light here.

 

[ShawnQ]

Re: 1990 Johnson 70 VRO

OBJ,<br /><br />Would it be difficult to check to see if the T-Stats are in the engine? Would water coming from the two ports on the backside just below the cowling be a sign of T-Stat removal?<br /><br />The mechanic told me that a lot of guys on the gulf here in TX do it because it is hot, and the T-Stat is one thing that is likely to stick closed and cause engine overheating. He said since most people dont run them when it is cold outside, they just pull the t-stat out to prevent them from sticking and causing damage. He said they are more succeptable to failure in the saltwater.<br /><br />He could be pulling my chain. If it matters, he had more fingers then he did teeth, and it was 10 minutes before noon, and he kept saying 'miller time' is only 10 mins away..so I'm not sure if he was feeding me BS to get me on my way, or being truthful..<br /><br />In general, how are these little engines? He also said that he would do away with the VRO and mix his gas/oil due to a possible VRO failure. I'd prefer to not have to mix it...<br /><br />Thanks<br />Shawn

 

[Solittle]

Re: 1990 Johnson 70 VRO

I run my boat in the Florida Keys and I run it with T-stats. My motors (V-4s) will not idle properly without T-stats. I have also been told that running without will reduce the life of the motors as they never get to the designed operating temp and will also have hot/cold spots since the water flow through the block, heads and exhaust manifold is not as it is designed to be.<br /><br />The arguement that T-stats are not needed because the water is warm here (wherever you are) does not hold water in my book. The operating temp of these motors (mine at least) should be around 145 degrees. The water dosen't come close to that even in the peak temps of summer.

 

[OBJ]

Re: 1990 Johnson 70 VRO

I think Mr Solittle answered the question very nicely....thank ya' sir.<br /><br />As far as the engine itself, the 3 cylinder loopers are a very good dependable engine. Take care of it and it will take care of you.<br /><br />As far as the VRO goes, lots of threads here on the forums covering just that...pro's and con's of VRO. I run VRO myself. I make sure the alarms work and the oil is being used. No troubles.<br /><br />By the way, your t-stat is located at the top of the head. There should be a four bolt cover there where the t-stat is located.

 

[rickdb1boat]

Re: 1990 Johnson 70 VRO

Shawn<br /><br />Put the T-Stat in and disable the VRO, as suggessed. These are fine motors as I have a 91' 70 HP Rude(exact same motor. different color) and it has served me well for 12 years. No problems at ALL! I would not trust the VRO on that year unless you have a new pump put in and all new lines going from the pump to the tank, carbs, ect. I got rid of mine right away, as I had been used to mixing my own for years. You know it in there and oiling properly when YOU add the oil. Do this and you will have a reliablr strong engine for years. BTW, I do decarb once a year, but when I pull the plugs beforehand and peek inside the cylinders at the pistons, they usually clean as whistle anyway. These engines. if run at a good clip do not leave very much deposits in the chambers. I even do alot of trolling, and it never loads up. Maintenence is the key! Take care of it and it will most definitly take care of you!