120 HP Johnson dying while under way

[rottenray6402]

I have a 1992 120 Johnson with VRO system intact. Since we have been having warm weather this winter I decided to go lake Trout fishing yesterday (Sunday). I hadn't run the boat for about 6 weeks and had added stabil to the tank before I stored it. Sat I started it on muffs and sounded good so Sun we headed for the Niagara River and it started right up at the launch. We ran about a mile into the edge of Lake Ontario where it died as we were cruising about 4000 RPM. It died just like we ran out of gas. :'(I tried to restart and it did start but only ran for a few seconds and died. We wanted to troll anyhow so I just started the trolling motor and used that for a few hours. I decided to try the big motor again and it started and ran good so we took off and went about 1/4 mile and it died again. It sounds like it is running out of fuel. I changed the water separator filter in October just for maintence and as mentioned put stabil in the fuel. My question(s) are: could part of the fuel system have ice in it causing this? I think I read where the fuel pump is hooked in with the VRO and it is possible to get some water in the oil tank? The temps here have been from 50 to 30 degrees. I'm still not to swift on the fuel system with the VRO so am looking for something that may be related to the cold? This motor had a new power pack put on it last spring and probably has 10 to 15 hrs on that. I realize it could be any number of things but I thought I would see if anyone here knew of something common to this problem before I take it to the marina. Thanks for any help offered.

 

[capngregg]

Re: 120 HP Johnson dying while under way

You're right, it could be a lot of things. I was helping a friend with his Bass Boat (same type engine as yours) a couple of years ago and we did some engine work (it was overheating and had some ignition issues) then fired it up in the driveway with the muffs on it and it ran fine.
We took it to the lake and idled around close to shore for a bit and tried a few accels and all was fine. We blasted off across Lake Ray Hubbard (Dallas,Texas) in the heat of the summer and all seemed great until we had gone about a mile and the engine died like it was running out of fuel.
We pulled off the cowling, did some looking at the engine and didn't really see any problems so we tried to start it up and sure enough it came back to life so we took off again. About a half mile later it died.
Eventually we pulled the fuel line off at the tank standpipe and stuck it directly into the fuel tank and restarted the engine. (we had some spare fuel hose with us) This time it ran fine for miles and miles, starting and stopping etc..
We put the boat back on the trailer took it home and pulled the pickup out of the tank and found that old varnish had come off the lining of the tank and was partially obstructing the standpipe filter. The agitated fuel would settle after the engine died and then it would start again until the screen clogged again from fuel agitation. We cleaned the tank out and all has been fine since then.
I wouldn't suggest sticking the line directly in the tank as we did necessarily but it got us back to shore without swimming so we were okay with it.
This may not be your problem but sometimes the simple things are overlooked. GOOD LUCK!

 

[kenmyfam]

Re: 120 HP Johnson dying while under way

Did you try priming the fuel bulb to keep it running ??

 

[OBJ]

Re: 120 HP Johnson dying while under way

Good question Ken.....I would also wonder if the fuel system had to be re-primed (using the primer ball) after each incident.

 

[tashasdaddy]

Re: 120 HP Johnson dying while under way

is the primer bulb collasing, going flat.

 

[rottenray6402]

Re: 120 HP Johnson dying while under way

Thanks for the replies, I regret to say that I never even thought to check the bulb to see if it was collapsed or not. I did think maybe something was in the tank floating up over the suction tube as I have seen that when I was an auto mechanic (many, many years ago!). It snowed last night about a foot and we are supposed to get another 10" today and tonight so it looks like it will be awhile before I can check it out. I live on a small lake so the next nice day I can launch and do some trouble shooting. I always have my trusty 6HP kicker to get me home. I appreciate the ideas and will check them out. Like I mentioned I'm not real swift on this VRO system so I thought maybe there was some sort of inherent problem when it was cold.:'(