NO WOT 1986 JOHNSON 70HP VRO

[MELSNER]

1986 JOHNSON 70HP VRO (VRO DISABLED)
Very Clean has not been run in salt water for at least 10 years
Which Has been working very well for the last 200 hrs of operation..
Running 5500 rpm on average sometimes push it to 6000

All previous problems with motor have been fuel line related so I try to get gas from stations
recommended by local marinas.

Hairline crack in inline fuel filter caused similar problem crack only opend when hit throttle...
So I am paranoid about fuel lines now.


SYMTOMPS
Started well but ran rough idels but choke handle would not rev, died when tried to put into gear
Noticed fuel leaking inside motor

ACTIONS
Replaced Fuel Filter and line back to eng connector (leak stopped)
Tried different fuel tank (did not try different bulb supply line yet)

RESULTS
Bulb seems to be pumping fuel well (not leaking inside motor anymore)
Starts well and idles
Wont rev up with choke lever ( seemed to rev like it should when I used finger on govenor )
Will run but only about 4500rpm enough to plane boat

ACTIONS
Tested Compression 110 all 3 cylinders
Installed New Plugs (old plugs were tan color but a bit fouled showing some wear)
Tested Spark top 2 cylinders appears very good (red/blue) bottom one was weaker (blue)
(SHOULD I STOP HERE AND Take to Marina for ignition check ?)

RESULTS
Starts well and idles
Still Runs rough
Still Wont rev up with choke lever

OTHER CONDITIONS
Prop appears to be in good conditions, some paint warn off, a few minor dents on edges
Pumps water ok for lower rpms replaced pump within last 50 hrs of operations

NEXT ACTIONS
Did not try different tank supply line
Carb cleaner
Check for water in Carbs
(looks like getting fuel pump out requires removing starter which removing air intake or cover anyway)

Fuel Line from fliter to fuel pump looks like it needs treplacement
Vacum line from pump to motor looks like it needs treplacement
Fuel Line from pump to carbs looks like it needs treplacement

 

[rickdb1boat]

Re: NO WOT 1986 JOHNSON 70HP VRO

I would do these first. Paying particular attention to #2, as fuel pump will not work properly if this hose leaks or is loose. And yes, you need to remove the air silencer and starter to get good access to the pump.

Fuel Line from fliter to fuel pump looks like it needs treplacement
Vacum line from pump to motor looks like it needs treplacement
Fuel Line from pump to carbs looks like it needs treplacement

 

[rickdb1boat]

Re: NO WOT 1986 JOHNSON 70HP VRO

This is what it will look like when you get those 2 items taken off:

 

[MELSNER]

Re: NO WOT 1986 JOHNSON 70HP VRO

Rick

I noticed a drip from carbs when squeezing ball.

I revmoved the air silencer and started then engine when I held my hand over the bottom 2 carbs i felt suction and when I held over the top carb it died.

Upon starting again I noticed gas squirting out of auto primer it appears that I have lost a line that connects the primer to the bottom 2 carbs, I will have to get some smaler fuel line to replace that so I might just redo all lines to carbs the are looking sad.

I also noticed only 2 screws holding vro pump in place so it cam out without witithout removing starter. I replaced all lines to pump and recaped vrooil.

 

[MELSNER1]

Re: NO WOT 1986 JOHNSON 70HP VRO

heres a pic of carbs with unconnected primer line it seems way to shore I dont know what happend to the rest of it. will have to examine more closely I have OMC Service Manual for Motor and the hose routing pages i can find are for 90HP and up only so it's a bit different but basically the same I guess. I would rather have a nice drawing of what it's supposed to look like... I had a bit of trouble getting back to this thread for some reason when I did the search feature it acts differently.
hmmm adding photos a trick too I guess I will do that later....

 

[MELSNER1]

Re: NO WOT 1986 JOHNSON 70HP VRO

Ok all new fuel lines and lines to vro pump and to primer... so much for trying 1 thing at a time...


Seems to run better now going for test in lake still found that it died when I put my had over the top carb what's with that ?

 

[rickdb1boat]

Re: NO WOT 1986 JOHNSON 70HP VRO

It shoud die when you block the air flow to the carbs. You should have one line from the fuel supply going to the primer and 2 lines coming out of it. One tees into the bottom 2 carbs and the other goes directly to the top carb. That's the one thing I forgot to take pics of when I replaced my primer a while back. Bet it runs alot better now. Let us know....

 

[MELSNER]

Re: NO WOT 1986 JOHNSON 70HP VRO

The lake test was a NO GO, it starts fine but wont rev when choked and dies when u try to put into gear, otherwise it will idle more smoothly.

The ball stays hard and I can see gas moving into the fuel filter.

The disconnected primer line accounts for gas that was evident inside motor, new fuel lines look pretty but no go.

Let me ask again the engine died only when I put my hand over the top carb, it did not seem to care much when I smotherd the bottom 2 carbs.

It does rev up a little when you hold the primer button in, but tends to die after that.

It does rev up if you finger the govener linkage a bit, but I didnt want to overdue that.

Where am I at now I have been reading the other threads a bit, should I suspect the diaphram in the vro pump ?

The cables seem to operate normally, it just doesnt rev.

I are the nuts at the bottom of the carb jets or just drains, is water a suspect should I drain bowls ?
I hooked same tank up to other boat and took it out last night (to take the edge off) and it ran great with that fuel.

 

[MELSNER]

Re: NO WOT 1986 JOHNSON 70HP VRO

I guess it's off to the marina on Monday, unless you can give me something else to check.

Currently it starts but wont go into gear like it's starving for fuel, it wont rev with choke.

It rev and die a bit if i hold primer button in the bulb is staying hard.

 

[MELSNER]

Re: NO WOT 1986 JOHNSON 70HP VRO

Ok so I dropped boat off 2 weeks ago... time passses

Mechanic hooks his tank motor and says carbs clogged up not getting fuel ... looks like water in carbs and jets are blocked. $350 to fix...

So fuel gets contaminated through what condensation in tanks or from the pump ($3/gal yikes) always buy from same station no ethanol.

Assumption bad fuel obtained/or condensation occurs... fuel is contaminated intanks boat runs fine on contaminated fuel one week and sits for a week contaminated fuel reeks havoc with fuel system.

What's the cure how do I prevent this from happening ?

Install water seporator/filter ?
Pull line and run motor till it dies after every outing ?
Store fuel in cool dry place with full tanks tank vents closed ?

 

[rickdb1boat]

Re: NO WOT 1986 JOHNSON 70HP VRO

You should not have that big of a problem with condensation where you are located. Possibly bad fuel(I would change stations for now), rain water or water coming in through the fuel tank vent would be more likely. This is if in fact it really is getting alot of water in the fuel. I would install a water separator filter for sure and moniter it closely until you are sure there is no water in the system. Do not run it dry each time, as one carb may run out of fuel/oil before the others. Then you are running that cylinder dry. Not good.....

 

[MELSNER]

Re: NO WOT 1986 JOHNSON 70HP VRO

So water in fuel an rust up the works that quickly ?

Both tanks are getting drained and I got a new supply line... guess a water filter/serportator is a good investment hopefully closeouts this time of year.

I was unseasonablly HOT (High90's) day and night those weeks but not much rain so I am thinking it my have increased condensation at bit.

I know the mechanic has to eat but $350 is enough to build my confidence enought to attempt the project, I just didnt have the time.

I am sure there is a thread here to guide someone through the process, how long per carb should it take ?

Does rebuilding carbs require removal and link and sync ?

Then again maybe I should stick to comptuers.... maybe start my carb rebuilding career with something more simple.

 

[rickdb1boat]

Re: NO WOT 1986 JOHNSON 70HP VRO

The carbs are not that big of a deal. Mostly the time you spend is getting them off (Removing air silencer, fuel lines, linkage, Etc). As far as the linkage goes, mark everything you can and try to get it back together the same way it came off. A digital camera is worth it's weight in gold when it comes to this. Should take you no more than 3 or 4 hours to do the whole thing. New rebuild kits would be a good idea when you do it. About $30.00 apiece from the dealer...

 

[jtexas]

Re: NO WOT 1986 JOHNSON 70HP VRO

I think $350 is about par. You can do it.

Manual is highly recommended. Here's a video tutorial:
www.meegsonline.com/tmd/TMDsVideoChronicle2.wmv

 

[h_lankford]

Re: NO WOT 1986 JOHNSON 70HP VRO

regarding source of water contamination: from my experience as mechanic on lawn and garden and rental power equipment, as well as my own boat ownership, I can say that most water is not in the fuel you buy, but in the method of storage (unprotected, condensation in not-full tanks, leaking vent or cap or other rain source, etc. ) Water from any of these sources will change your gas into orange jello. Harvey