1986 Johnson 70 Hp VRO Rebuild

[Blacksting]

Re: 1986 Johnson 70 Hp VRO Rebuild

worked with my gimbal bearing . put it in the freezer for 6 hours and it slid right on like butter .

 

[Blacksting]

Re: 1986 Johnson 70 Hp VRO Rebuild

I tend to agree with you . afterall, to remove .001 of an inch you'd probably have to rub on metal for about 5 minutes. think about it , tiny micro particles being picked up between the tiny micro gaps of 1000 grit paper . it all adds up to almost nothing . great post.

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

So Friday evening my son comes over and we were talking about starting the motor on Saturday morning, but I wasn't sure I would have time due to all I needed to get done before an afternoon appointment. So he says, "why not now?"

So...we hurried and got a couple of things done that needed to be done before it could be started, and here is the result. I should have been 'with it' enough to realize that after a couple of cranks, I should have pumped the fuel line primer bulb, but it started nonetheless, on the seventh crank, on one cylinder, and all three kicked in on the eighth.

The garden hose I had in the water bucket kicked out, and was spraying a fine mist in the air. I wasn't sure were the mist was comming from, so I turned the motor off. I thought it might have been form a crack in the block or head that I had somehow missed.

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

The second video is after setting the throttle pick-up timing and idle rpm settings. We ran it about half an hour in all, most at a high idle, so only 9-1/2 break-in hours to go!! I think it sounds great, and as my son said, "can't wait to hear her screaming up across the lake!!"

 

[Blacksting]

Re: 1986 Johnson 70 Hp VRO Rebuild

she sounds great . so, your son likes screamers , eh ???,...

 

[BillP]

Re: 1986 Johnson 70 Hp VRO Rebuild

Nice work. I wouldn't worry about the crank. I did a badly scored journal on 50hp 3 cyl Metro car engine crank with 400-1000 grit. The only difference is I didn't use a shoe string. It has 60k+ miles on the job and most of it doing a 100 mile daily commute running 4500+ rpms on the interstate. I've been meaning to drop the pan and check it but so far nothing is out of the norm...

bp

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

she sounds great . so, your son likes screamers , eh ???,...

apparently only in boats….

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

Nice work. I wouldn't worry about the crank. I did a badly scored journal on 50hp 3 cyl Metro car engine crank with 400-1000 grit. The only difference is I didn't use a shoe string. It has 60k+ miles on the job and most of it doing a 100 mile daily commute running 4500+ rpms on the interstate. I've been meaning to drop the pan and check it but so far nothing is out of the norm...

bp

Thanks, bp. I guess the best thing to do is (as it should be anyway) to break her in gently, then run it like you stole her. I can't imagine I did any damage at all. OMC cranks, so I've been told are harder than most, and come-on, 1000grit, really? and by hand to boot. I expect to get years and years of butt-kicking, tube flipping fun out of her!!

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

Got the steering cable back in last night. I had taken it out because it was unusally stiff. I couldn't even begin to "palm" the wheel; almost took two hands to turn it. I hung it up, cut a small hole in the corner of a gallon zip-lock bag, slid it up to the rack, taped it off to seal it, and squirted light oil down through the rack, working it back and forth with the helm for about four weeks. I also took a bicycle inner tube, cut about an eight inch piece and hose clamped it to the motor end, after putting about four ounces of light oil in it as well. I think the oil at the engine end did more to free it up than the helm end. Makes me think that water had migrated in through the steering tube. Anyway, I can now turn it using the palm of my hand, though bending the cable to make the turns behind the dash and at the splashwell did seem to stiffen it up a bit. I also think it's about six inches too long, since the bends were quite tight in order to get the rack pushed far enough to the starbord side so as to match up to the helm. Tha cable says 13ft, 6inch, so if I do replace it in the future, it will be with a 13ft. cable.

 

[orbanp]

Re: 1986 Johnson 70 Hp VRO Rebuild

Borrowed a compression tester this week end; 135psi top, 135psi middle and 134psi bottom. I'm very pleased, and gotta remember to write this in my service manual for future reference.
...
~ more later ~

Nice rebuild!

My guess is that the compression will be higher when the engine is run in.

Good luck, Peter

 

[maineboat]

Re: 1986 Johnson 70 Hp VRO Rebuild

Finally splashed the boat last Saturday; My son and I took it out for a quick run to try to set the wot timing, but the sun was so bright, I couldn't see the marks well enough, so I left it alone. I'm gonna have to steal some of the wife's nail polish, and highlight the right mark. I'm thinknig hot pink, or fuchsia
I've got to say, I was very happy with the way the engine ran!! With 4 adults and a 9-year old, and pushing it only to about 4000rpm since it's not fully broke in yet, it would run up to about 32mph on the gps. I thought this was quite good, especially considering my prop is not that great; in fact, the power head would vibrate some at different rpm's, and I figure the prop is causing this. I'll be looking for a new or good used one. When we came back in, and after I dropped all the passangers off to load gear in the truck and bring it down to the launch, I took her out for a quick run, just to see what is would do with just me in it. Would you believe the gps showed 38.8mph, runnign at about 5500rpm!!! I didn't want to run her at wot for too long, as I only have about 3 hours on the motor, and the wind was a little gusty, and I could actually feel it pushing the bow around, so I didn't get it trimmed for maxumum speed. I'm quite sure that on smoother water, it'll do 40 without any problems.

BTY, in all the excitement, we forgot to take any pictures or video, so next time out, we'll get some

Very excited!!
~ more later ~

 

[chris3298]

Re: 1986 Johnson 70 Hp VRO Rebuild

Old thread but wanted to say thanks for sharing, I just picked me up a 86 56 ci 70 hp Johnson yesterday which I plan to have it hoped up for drag racing. These are some badass little motors i have personally seen a guy take one of these motor and put it on a home made 11 foot wooden boat running about 80 mph. Really amazing what they can do. Don't ever sell that motor and if you do you're get a lot for it.