Some questions from a newbie boat motor owner (Johnson 70 VRO)

sssports

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Hello everyone !

A few weeks back I received some awesome help on here and it was and is much appreciated, now after reading a few threads, I think I need to maybe do some things to this motor (winterizing)

As per the very generous help from everyone here I plan on replacing the entire water pump and the thermostat, I already replaced the plugs, (which were in dire need of replacement) the tips were wore down to paper thin and the center electrode was below the ceramic, so I am going to assume that all important aspects of this motor need to be serviced i.e. thermo and water pump.

I noticed in one thread that a lower unit was ruined from water freezing, and I am in St. Louis MO so we get freezing weather. I just got this motor and boat, and ran it in a large 55gal poly water barrel, so my question is, do you need to drain the lower unit ? Does it hold water that will crack it ? And if so is it the lower most plug on the lower unit ? We have only had one spell of cold weather since I ran it, and it seems to be fine at the present time, but I sure don't want to ruin this fine running motor before I even get it to the water !

Second question is....about the power tilt/trim which it has on the OMC throttle handle and on the motor cowling. I am looking at purchasing a guage set for this motor i.e. Speedo, tach, trim, water temp. But every guage set I find says sensor needed, and I can't find the sensor for the tilt/trim guage, I have searched this site and the internet to no avail, I found the sensor for Merc, but none for OMC or Johnson. I recently found a small console made for Johnson/Evinrude that includes a trim guage, but it too has no sensor with it either.

And please forgive my ignorance, but if the motor has power tilt, is that not the same as trim ? I know there are power trim tabs on some boats, but if the motor tilts is that not motor controlled trim ?

And one last question, does this motor have an alternator for charging the battery while running ? Am I guessing right that it has a magneto type alternator ?

Thanks in advance for any and all help with my questions.

Marty
 

tashasdaddy

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

marty, please post year and model number. you need to get a johnson manual for your specific motor, if you are going to do the maintance. Yes, i would change the oil in the lower unit. the bottom plug is the drain and fill plug, the top one is the vent, it will not drain with opening the vent, then the new oil goes in the bottom, and fills til it runs out the top. trim is the slow moving tilt of the engine(work the same switch) only goes several degrees, then it will speed up to raise the engine, this is tilt. when running the engine, at speed the engine will only tilt up the amount of the trim. most engines your size, have rectifer that converts the AC current of the stator to DC current to charge the battery. not knowing the year & model can't give you part number to the sending units.

also when changing the lower unit oil besure to replace the seals on the plugs, this is the most common place for a leak. you need outboard lower unit oil.
 

sssports

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

Hi Vice Admiral !

The motor is a Johnson 70 VRO with the VRO removed by some previous owner, now running on 50-1 mix in tank. The year of the motor is 88.

Also can you tell me if I need to remove a plug on the lower unit to drain water out ? I just assumed that all the water drained from the motor when it shut off, if not I need to attent to that immediately ! And yes I plan on changing the lower unit oil as well before it goes in the water this coming spring.

The good folks on this forum gave me step by step on draining and filling from the bottom until it comes out the top plug.

Since I have to take off the lower unit to change the water pump, will I need to replace a gasket between the upper and lower unit ?

Thanks for all the great help on this forum !

Marty
 

WillyBWright

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

No gasket at the joint and don't be suprised if water shoots out in unusual places when you get it back together. That's not unusual and just excess. The motor will drain itself as long as it's straight vertical. The sending unit will have to come from a Johnnyrude dealer. Gauges can be had any number of places. Many are universal and will work with any motor. Trim gauges are one example of brand-specific gauges. There were bolt-on tilt units that just tilted. Chances are yours is a trim/tilt unit. Tilt only units mostly went on older units than yours, but might fit yours as well if it wasn't originally equipped with one. They were add-on kits and not likely to be incorporated into the throttle/shift lever.

Trim tabs act kinda opposite of trim/tilt. Trimming the motor can lift the bow (trim UP) or drive it into the water (trim DOWN). Trim tabs can only push the bow down. Trim tabs are useful when you have a boat that always lists to one side while underway, or boats that porpoise at full trim.
 

tashasdaddy

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

the reason for changing the lower unit oil now, is any water has gotten in there, it will freeze and crack the lower unit. change it now rather than take a chance. it's part of winterizing.
 

sssports

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

Vice Admiral,

THANKS a bunch, I thought you had overlooked the question, but as I said I am a newbie, and did't realize that. I was just at the Johnson web site and looked at the schematic for my motor and in doing so realized that all the seals between the oil and the water are internal and the lower unit itself where it bolts up is not sealed.

Since I am making a nuisance of myself (chuckle) and if you have the time for yet another question, is it really necessary to change the entire water pump or just get the rebuild kit ? In looking at the Johnson site schematic on the motor, they listed everthing that is included with a water pump rebuild kit, which is as far as I can tell everything BUT the housing. Would it be a good idea to replace the housing as well on this old a motor ?

I figure I will just change the oil and water pump at the same time. Any harm in just draining the lower unit oil and leaving it drained until I replace the water pump ? Of course putting the plugs back in to keep out moisture and debris.

The guage on the console I am thinking of buying is a Faria, so hopefully Faria will be able to supply me with the sender unit for the trim guage.

Thanks for all the helpful info !
Marty
 

sssports

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

tashasdaddy said:
the reason for changing the lower unit oil now, is any water has gotten in there, it will freeze and crack the lower unit. change it now rather than take a chance. it's part of winterizing.

Vice Admiral,

Well just got done draining the Lower unit, the oil is clean, no foaming or whitening so no water in it. The bottom drain plug had just a speck of metal on it, not enough for any concern. However the O ring seals on both plugs were shot, I am surprised it didn't leak waten in or oil out.

So what is the complete winterizing process for an outboard motor ? Sure would appreciate the info so I can do this right.

Thanks !
Marty
 

JUSTINTIME

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

u need to do lower unit oil
replace the 2 o-rings on the vent and drain plug
stabilize the gas and start the motor up to run the stabilized fuel through the system
fogg the motor with fogging spray
then drain the carbs
spray fogging oil down each cylinder and u are ready to go
make sure u keep the motor tilted down also
 

DHPMARINE

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

One answer for you about the waterpump.I advise my customers to tear it down and see what is needed.If everything is good,no wear marks,scratches or broken gaskets,or orings,just put in a new impeller.Make note of the date,and do it again in 2 years.If parts are worn,put in the whole kit.I think now the kit only comes complete with the housing.

DHP
 

tashasdaddy

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

get the seal for the plugs, and put oil back into the lower unit. right now it has air in it, heating in the day and cold at night will create condensation inside the lower unit, and it could start rusting. right now it is not protected. you can drop the lower unit without draining the oil, to do the impeller. i've never done it as i change the oil when ever i drop one, to do an impellar.
 

jtexas

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

If you will be using your boat during the winter no real winterizing is necessary just make sure to leave the motor tilted down to drain all water from the powerhead before trailering home. If it'll be stored for more than a few weeks, treat the gas with stabil, and do the fogging procedure recommended by justintime, Deep Creep (Seafoam in a spray can) is good for that.

Your motor has a 6-amp unregulated alternator.

A manual would be a real good idea, iboats has seloc or clymers are pretty good, original OEM shop manuals are available at kencook.com or marineengine.com

The manual calls for OMC Adhesive 6 on the lower unit; I use permatex #2, works fine.

You have to disconnect the shift linkage under the bottom carb to drop the lower unit.
 

iwombat

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Re: Some questions from a newbie boat motor owner (Johnson 70 VRO)

Better yet, get a bag of seals for the lower unit oil plugs and (here's the tricky part) remember where you keep the extra ones. You'll be changing it often enough, might as well stock up.
 
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