Reassembly of 84' Johnson 70 Tips

[Socak]

What are some tips on the reassembly of a motor that you would not think of or are not in the manual? Also what do you do if the ring gaps are out of spec when you put them into the cylinder to for the gap clearance?

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

first thing i do is get water into the hot pockets between the ports by drilling holes for it to enter & EXIT , then i go to cylinder head there are some pockets where water enters but does not exit wich i find does not cool the head enough , on the sides you will find them . if you are to use your motor in sea water there are a number of things i do , to make it run for another 50 years . cheers

 

[Faztbullet]

Re: Reassembly of 84' Johnson 70 Tips

Also what do you do if the ring gaps are out of spec when you put them into the cylinder to for the gap clearance?

You bore cylinder to the next oversize as its past it .004 wear limit......

What are some tips on the reassembly of a motor that you would not think of or are not in the manual?

Do the factory cooling mod as it helps all 3 cylinder engines(see below), use primer with your gelseal, put a thin coat on center main as it tightens up race(E-tecs do this), rebuild fuel pump and replace all fuel hoses, and replace t-stat.

 

[Socak]

Re: Reassembly of 84' Johnson 70 Tips

Yes I will be running the motor in salt water, so what are some other things you do to them? I have replaced the thermostat, rebuilt the fuel pump and replaced the line running from the pump to the carbs. How do you test the carbs to make sure they moving enough fuel through them? I replaced the jets in them, which I later figured out probably was not so wise.

 

[boobie]

Re: Reassembly of 84' Johnson 70 Tips

The only way to test the carbs is to take the mtr out and run it.

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

your motor will have the same sort of adaptor plate , i have found many 70hp with this problem in the adaptor , due to salt corrosion a hole right through the exhaust outlet , i mix westsystems epoxy with biulding cement & piece of carbon fibre cloth & place it on the inside & out side where the hole is & epoxy the inside of the adaptor plate , then i also drill & tap a hole where the sqaure is there is a casting provided there its on the bottom of the outside curve in the sqaure , for some reason the factory never bolted it there i make it bolt then directly onto the other part of the adaptor wich goes under neath this stops the curved area lifting when it gets hot ,
http://forums.iboats.com/johnson-ev...ok-out-when-buying-1970-ties-70hp-532243.html

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

the very first thing i do when i rebiuld a 70hp is get rid of the hot pockets & change or modify the adaptor plate if used in sea water there is another why to change the manifold plate by useing 10mm marine grade aluminium & drilling holes in the block to get more & faster water flow through the motor , now in this case ive epoxy coated the whole inside of this motor with execellant results , my tests have so far froved secessfull ,
http://forums.iboats.com/johnson-ev...nts-experiments-1974-70hp-johnson-528873.html

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

another one of my conversions on these motors
http://forums.iboats.com/johnson-evinrude-outboards/durbans-con-rod-mod-531098.html

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

this may save your tilt tube for years to come epoxy paint with 2k the tilt tube between the brackets in the middle of the transom the best way to do it is remove it & clean the inside of tube with a round file first then plug one end & pour paint in you will be surprised how they corrode with salt over the years ive had them with holes corroded right through , or better still is find 22.2 mm carbon grafhiet tube , good luck m8t

 

[Socak]

Re: Reassembly of 84' Johnson 70 Tips

How big of a drill bit did you use?

the very first thing i do when i rebiuld a 70hp is get rid of the hot pockets & change or modify the adaptor plate if used in sea water there is another why to change the manifold plate by useing 10mm marine grade aluminium & drilling holes in the block to get more & faster water flow through the motor , now in this case ive epoxy coated the whole inside of this motor with execellant results , my tests have so far froved secessfull ,
http://forums.iboats.com/johnson-ev...nts-experiments-1974-70hp-johnson-528873.html

 

[durban]

Re: Reassembly of 84' Johnson 70 Tips

i used a 5mm bit the hole you have to drill at an angle for the exit hole there must be a inlet hole & out let hole other wise the water gets traped causing a supper heated steam pocket , the water has to flow through , there is another hot pocket at the very bottom by the exhaut out let , looking at the sqaure outlet it will be on your right hand side in the corner , cheers

 

[Faztbullet]

Re: Reassembly of 84' Johnson 70 Tips

my tests have so far froved secessfull ,

Not trying to be a wise arse but running in barrel with no load really proves nothing, you need to run this motor with a load applied so it can make some heat!!!!, then that will test your epoxy and modifications.

Socak.. I have built probably rebuilt about 150 of these motors with nothing but the factory mods....just reassemble with new gaskets and check exhaust plate with steel rule to check for parallel and plate warp...

 

[Socak]

Re: Reassembly of 84' Johnson 70 Tips

Is it wise to do the factory mod of moving the water flow indicator from the side of the exhaust to the top of the exhaust?

my tests have so far froved secessfull ,

Not trying to be a wise arse but running in barrel with no load really proves nothing, you need to run this motor with a load applied so it can make some heat!!!!, then that will test your epoxy and modifications.

Socak.. I have built probably rebuilt about 150 of these motors with nothing but the factory mods....just reassemble with new gaskets and check exhaust plate with steel rule to check for parallel and plate warp...

 

[Faztbullet]

Re: Reassembly of 84' Johnson 70 Tips

Is it wise to do the factory mod of moving the water flow indicator from the side of the exhaust to the top of the exhaust?

Yes....prevents possible air lock/pocket in block.

 

[Socak]

Re: Reassembly of 84' Johnson 70 Tips

I got everything assembled and attempted to start the motor a couple of times. It started and fired this morning and last night, but then it stopped running. Now I can get the motor to turn but it doesn't seem to want to fire. Spark and fuel all seem to be good but it just doesnt want to just catch and fire and keep running. Is this a timing issue? Compression is good 115 on all cylinders. I can hear the primer solenoid pump fuel into the carb so that appears to be good too. Not sure what else to do to get this thing running.