Johnson 70 vro no power

[mnkelsner]

I boat a with a 1986 Johnson 70HP VRO previous owner had VRO disabled, took it out for about 2 hours one day and 4 hours the next day and everything everything worked great other than a little rough at idel. <br /><br />I topped off 2 tanks with fresh batch of 50:1 with premium gas, I put in and it started rightup and it seem to run really rough, I had to start it several times until it warmed up it was pumping water fine.<br /><br />I was able to move away from the dock a hundred <br />yards or so but I was not able to get more than <br />2000-3000 rpm out of it, it kept running but just would not rev up ? I switched tanks and kind of<br />fiddeled with the hoses with no luck. I did not want to run it anymore so I had to get the electric oar out.<br /><br />I cleaned the fuel filter and put in fresh plugs<br />the local marina recommended NGK plugs, I hooked up the hose to it and it started up ok but I had to hit the choke prime to get it smooth out.<br /><br />I returned to the lake with it and and it did the same thing no power, any ideas ? Something simple like the fuel lines, tank cap or vent, bulb ? <br /><br />If the plug on the VRO overide fell out and cuase this kinda problem ?<br /><br /> clueless... should I find a mechanic ?

 

[rickdb1boat]

Re: Johnson 70 vro no power

Did you check the fuel line and bulb to see if it was firm when you squeeze it? Try running with the gas cap off or loose. If the fuel line is old, I would start there and replace it, as it may be colapsing internally. Have you tryed pumping the bulb, when it won't run? Give a little more info, please. Sounds like it's starved for fuel!

 

[JB]

Re: Johnson 70 vro no power

Hi, Mike.<br /><br />1. Don't waste your money on premium fuel. 87 unleaded is fine.<br /><br />2. You are probably running on less than all 3 cylinders. Do a search on power loss at WOT and follow that advice to find which cyl(s) is dead and how to isolate the cause.<br /><br />3. Your Marina obviously makes their profit on NGK. They are decent plugs. OMC used and recommended Champions. 'Nuff said?<br /><br />Good luck.

 

[mnkelsner]

Re: Johnson 70 vro no power

At least you make me think that it is some kind of mistake I am making with the hookup, and hopfully low $$$ fix.<br /><br />I hate to sound like a total id 10 t but here goes<br />the old seahorse was a 1955 10hp Johnson you sealed the tank pushed the button a few times and you were set. <br /><br />With the new seahorse I got it right once but maybe I am not doing something right this time. <br /><br />I have a plastic OMC tank with a vented fuel cap and a hose with a bulb on it, when I squeeze the bulb I can feel & hear the fuel going through but I also thought I can hear air esaping on the motor when I pump it.<br /><br />Should the vent on the tank be open or closed ?<br /><br />I noticed that the tank was bulging the other day so I opened the vent but cannot remember if I it ran well open or closed. I tried it both open and closed without success.<br /><br />The bulb also seemed to collapse at one point while I was pumping it like there was a vacum or nothing was going through. <br /><br />The fuel connector at the motor is loose as though<br />a retainer clip is gone, the fuel lines at the filter seem to be on tight but the retaining clips could probably be tightened another notch, is that finger tight or can you use needlenos pliers on those plastic clips ?<br /><br />Pushing in the choke primer did seem to get more fuel through better.<br /><br />

 

[rickdb1boat]

Re: Johnson 70 vro no power

nuboat,<br />Yes, the vent must be open when you are operating the Motor. Otherwise you will create a Vaccuum in the tank and not get much, if any, fuel delivery! If the bulb is collapsing, it is most surely a clogged or closed vent causing your problem! Also, like I said, do yourself a favor and get a whole new fuel line and bulb assembly. That will have new connectors on both ends and you won't be fiddleing around trying to tighten the retainers or bending them. Well worth &15.00 for a new fuel line! Also, make sure the vent on your tank is open and clear!

 

[mnkelsner]

Re: Johnson 70 vro no power

JB NGK's were expensive they wanted $15 a pop for them until I complaied and then they still soaked me for $10 I 'm sure they focus on the Chicago Vacation crowd.<br /><br />Last week I had one tank of 87 and another of 92 and they both seemed to run fine. I topped them both off with 92 I mixed in another can.<br /><br />I will search for "power loss at WOT" (what does wot mean ?)

 

[rickdb1boat]

Re: Johnson 70 vro no power

Wide Open Throttle

 

[mnkelsner]

Re: Johnson 70 vro no power

Well walmart was out of omc fuel lines for $15, so I tried the two spares that came with the boat and one seemed to work a little better but boat did not run any better. <br /><br />I pulled the plug wires one at a time and it did not want to start at all with the top plug out.<br />The others did not seem to make as much differance anyway.<br /><br />I pulled all the plugs and the bottom one looked like brand new top two were black and wet all the way up the threads, I peaked in with the bore light and all three pistons looked the same dark brown in color maybe kind of spackled looking but smooth i guess. What should they look like ?<br /><br />One last thing... the top plug would not go in smooth and when I looked at it, the top two threads were full and stripped so I just put it back in a little and will deliver the boat to the marina Wed before I turn a $15 problem into $500 one.<br /><br />Marina wants $150 for a tune and afraid to know what they might think of $tripped plug.<br /><br /> <br /><br />Also I did find a broken wire brown in color with a rubber connector on it coming down from top bout<br />to where the fuel filter is but did not seem to have anything to hook to or other half of the wire<br />could this be something that was connected to vro system ?

 

[rickdb1boat]

Re: Johnson 70 vro no power

^

 

[rickdb1boat]

Re: Johnson 70 vro no power

Yes. It's probably for VRO! As for spark plug being stripped, they will have to install a helicoil, unless they can run a thread chaser in there, which should not be more than $50.00 or so. I had one done for 30, about 2 years ago.

 

[mnkelsner]

Re: Johnson 70 vro no power

Rick <br /><br />I am cursed... I dropped the rig off to the local marina today and the first thing the tinker asked me was had I been running ehtanol in it.<br /><br />Well right before I went out and stared having trouble I stopped at the a station and mixed 5 gal in a seperate can and topped off both of my tanks. I went back and checked the station and sure enough they had changed to 10% ethanol product.<br /><br />I did not use any ethanol previously and its 5 minutes to the lake from the station would it eat something up in my fuel system so quickly to cause the no power at wot ?<br /><br />

 

[rickdb1boat]

Re: Johnson 70 vro no power

I douht it! Not one tank full! do a "Search" at the top of this page on "Ethenol" to find out more! Good Luck, I'm on the way to the Lake this AM to take care of some problems on my boat, too! Talk to ya Next Week!

 

[gg05]

Re: Johnson 70 vro no power

I have the same engine and you are definitely running on 2 cyls. It will idle fine but won't plane, right? you are either not getting spark or fuel to 1 cyl. which is the best scenario. Or you lost compression, bad news. Sorry

 

[mnkelsner]

Re: Johnson 70 vro no power

I took it to my local marina and the said I have good spark and good compression, but that bubbles on the plugs indicates water in the fuel system and is probably the result of poor quality fuel from a netorious local gas station.<br /><br />The tinker also mentioned putting in an additive to get rid of the water in the full tanks (does that me dry gas)and that he would look for water in the carbs next. <br /><br />Would probably be back on the water already if he did not have to wait for a head gasket to come in, he had to pull the head and put in a helicoil beacause of my zeal in stipping out a plug.

 

[mnkelsner]

Re: Johnson 70 vro no power

OK back in business engin again runs fine... if anyone is still listening the marina dinged me $300 for a helicoil and carb clean up. <br /><br />I did have good compression and good spark and found my carbs were gummed up and full of oil and water. They want to blame my choice of gas stations and a dirty fuel tank.