Durbans water flow improvements & experiments on 1974 70hp johnson

[durban]

I find it a common problem with 1970 ties motors ,where water gets in through the exhaust ports , especially the center port ,& there are 2 hot pockets on either side of the center port where no water gets in , ive made some improvement there , have a look at the picture & u will see some green & yellow wire , that's just to show u where the water will flow .
along the top edge of picture u will also see some extra holes in the block , i put them there cause when the exhaust manifold cover goes on , over the years salt builds up between the gasket & exhaust cover that goes on top of the manifold , between the 2 there is very little clearance & i have found that salt builds up between them restricting the water flow ,so now i have water flow going between the exhaust box cover & manifold cover into the block the holes between the manifold cover & block are spaced apart , so that the water can fill the area between exhaust cover & cover first before going into the block
u will also see 2 black blocks that ive cast in around the center port , that is where the manifold will bolt onto , i find that with all the heat around the center port , water gets in , cause of insufficient bolting around that area
the blue wire shows u what ive done & ive made my own gasket , the blue wire will show u ,what ive done to the gasket this is done to stop water getting into the exhaust box , any ? PLEASE ASK
also some improvement on the cylinder head drilled some holes into the hot pockets the blue wire will show u the water flow now

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

the green wire will show u the holes drilled in the exhaust manifold

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

the blue wire shows what has been done to gasket & where the manifold will bolt onto note what ive done to the center port the port has been modified , k

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

the little nearly triangular shaped hot pocket on the right hand side of the center port does have a hole in it , the water will flow through it and come out between the top of the manifold & then circulate between the manifold & exhaust box, the blue wire will show u wher it comes out through the manifold , k cheers for now

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

the exhaust manifold has been bolted today , note what has been done around the center port , to stop it lifting & that is where the water gets into the port , causing all the damage ,k uploaded the photo to show

 

[kodibass]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

Man' I wished you lived next door to me, Your skill level is so over my head it ain't funny.. Guys like you make me want to sell my meager tools and go make mud pies. Great work!

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

Thanks for that m8t ,I am a ticketed Boilermaker/welder by trade , unemployed at present , have taken a bit of a holiday this summer to spend time on something i love doing , fishing & collecting scrap , & fix them up , that way i dont spend my money to go fishing the scrap pays for it all , cheers

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

I found this on the scrap a few days ago , its a solid brass/bronze gearbox , it weighs 35kg , & In excellent condition , the bearing turn as smooth as , i couldn't be-leave it , i have no use for it , but checked the price on metals , so may go sell it for gas money , u see how i do it k , cheers

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

I found this motor on the scrap to , & rebuilt it , and its also the only motor in the world , with my conversion on , that nobody in the world has ever done , points to timebase , i will put it in your museum in the USA , K ,

 

[ultra353]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

You do fantastic work, Maybe a change of jobs?

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

what you can do , the gasket that goes between the exhaust manifold plate & manifold ,INCREASE the thickness of the gasket , & cut it there where the blue wire shows , by doing this more volume of water flows between the 2 manifolds .I have found that the gap between the 2 manifolds is +/_ 1mm . now when you put a gasket on {the one you buy in the shop} its +/_ 0.5 MM thick ,between the 2 faces , the salt builds up under the gasket & manifold plate , & OVER THE YEARS , eventually no water gets in there , because the salt has blocked it , k , because of the little clearance in that area , by increasing the gasket THICKNESS & CUT IT WHERE THE BLUE WIRE SHOWS YOU < by doing this you get more clearance & better flow of water & prevents salt build up in that area ,

IT,S TRUE WHAT SOME FOLKS SAY ABOUT THESE MOTORS THAT KNOW THEM WELL ,THAT THE PORTS GET WATER IN THEM , due to i inefficient cooling around the ports because of problems like what ive just showed you ,k ,have a good look at the photos & study them then you will understand what iam on about

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

now here is a perfect example of what i was talking about yesterday , that's why i recommend you increase the gasket thickness & cut where i showed you , k some of the salt has been removed , but i can a sure you the water does not get in there , take my word for it , cheers

 

[durban]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

this is what i did to stop the manifold plate to allow water in to the center port & drilled extra holes every wher & increased the gasket thickness& modified the gasket , read the thread & follow

 

[phillnjack2]

Re: Durbans water flow improvements & experiments on 1974 70hp johnson

Wow .
A few manufacturers need to take note of your improvement work.
Its things like this that make engines last longer and give them better reputaions = better sales.

If you lived next door to me i would kidnap you and lock you in my garage and keep you to myself for all engine work.
People like you are so talented its unbelievable.
You make everything sound so simple, yet to us mere mortals you are a genius.

Your work is brilliant, but why didnt the engineers at omc do this in the first place ?
By doing these mods i can see that the water flow is much better, and that the salt build up would be less.

Just a couple of questions.........
1/ is this modification going to cause the engine to run too cool due to lowering water pressure and getting more volume ?
im not saying it will, just wondering if it would run cooler due to these mods.
2/ By running cooler,would it harm the engine in any way ? or is it better for these engines to run a touch cooler.
3/ Also would it be possible and/or any benefit to fit a extra flushing attachment to this area as well. ?

Personaly i think this looks a very good mod to do, and one that would benefit all outboards of this type.
If i had the tools and brains, i would be doing the very same thing today to mine.:redface:

Is this pretty much the same for the later 3 cylinder engines, ?
mine is a 1995 and im seriously thinking about getting this done if its the same type of thing.
Salt build up is the main killer of many outboards, to me it seems that none of the major outboard engine
manufacturers done much to solve any problems in this area.

Ive seen many outboards when taken apart full of the dreaded salt and can never understand why so many little
tiny orifices are put in, instead of bigger holes etc.
The makers of these engines know only too well that the engines will be used at some point in a salt water enviroment
and no ordinary flushing will get everywhere to clean the engine.



phill..