Power loss in 1977 Johnson 6HP (1/2 power possibly)

[oldboat1]

could help. Heat up some water in a large cup (I use the microwave), and dip the t.stat -- see if it opens. (Grip the frame with a pair of tongs.)

 

[Crosbyman]

Primer bulb in the fuel line between the tank and the Johnson? Is that the "fuel pump"? If so, my primer bulb is new (as is the 2 fuel lines). Or is there a "fuel pump" inside the Johnson?

Thank you for your comment!!!!

so..... did you try hand pumping to fuel line bulb when it bogs ??????

 

[jimwalt]

so..... did you try hand pumping to fuel line bulb when it bogs ??????

No not yet. I will tonight after work and report back.

One thing I do notice is that sometimes my gas tank whines, makes the sound like a cow mooing. Later when I remove the cap it is extremely hard to make come off.... and I'm a pretty strong guy too!

 

[Crosbyman]

well then that sounds like a tank venting problem ... discussed above

just run the engine with the gas tank cap loose ....and pump manually if it bogs again

​fix the venting issue any gas sucked from the tank must be replaced by incoming air in the tank

 

[jimwalt]

So I took it to the lake for about a 10 to 15 minute spin. I ran it full throttle with the choke all the way in (no adjusting it at all) AND IT WORKED PERFECTLY!

So how's that possible? I'm feeling it's a fluke. The only thing I've done since yesterday is the small piece of wire in the hole where the bolt #29 was at (what really could that have done or helped?) and I opened the fuel tank to relieve all the pressure before starting out. That's it.

So is this a fluke that it just happens to work perfectly today?????

Thank you.

 

[ondarvr]

Like you were told, the jet is behind the bolt, you cleaned out the gunk with the wire.

 

[jbuote]

So I took it to the lake for about a 10 to 15 minute spin. I ran it full throttle with the choke all the way in (no adjusting it at all) AND IT WORKED PERFECTLY!

So how's that possible? I'm feeling it's a fluke. The only thing I've done since yesterday is the small piece of wire in the hole where the bolt #29 was at (what really could that have done or helped?) and I opened the fuel tank to relieve all the pressure before starting out. That's it.

So is this a fluke that it just happens to work perfectly today?????

Thank you.

​Along with what ondarvr mentioned, venting the gas tank probably helped too.. .

I'm NO expert by any means, but...
​As mentioned before, (crosbyman and jimmbo I think) air needs to get into the fuel tank to replace the volume of fuel sucked out by the fuel pump..
If no air can get in the tank, then fuel will eventually stop flowing..

​So venting your tank also helped I'd bet..
Maybe the combination of gunk out of jet, and venting the tank gave you 10-15 minutes of perfect running??

​Might be time to look closer at fuel tank venting to be sure the valves etc, (as jimmbo mentioned..) are working like they should and get you more than 10-15 minutes?
​
I get the feeling the carb issue is solved because it ran great for you for that long..
​Now if it sputters out again on an even longer run, I'd be looking at the tank and venting..

​Just a thought..

​Glad to see you had success though!!!

 

[jimwalt]

Thanks Guys!

My 10 to 15 minute (probably closer to 10 minute) run today was just to see if it slowed down after 30 seconds like it did yesterday......

When I cleaned out the jet all I did was stick that tiny little wire in there may 1/4 to 1/3 of an inch. Nothing came out on the wire so I thought maybe that was just a waste of time, unless it was the size of a grain of sand that I can't see.

I'll be watching it each time closely for the next couple outings expecting the problem to return........ yet I hope it doesn't. If so, I will be back here posting again.

I also suspect maybe the venting with the tank could be a problem. I hate to pitch my tank to the curb because it has a built in fuel gauge. The new ones at Walmart that cost $49 and also need a $5 connector don't have the gauge (and I'm frugal).

Thanks again.

 

[jbuote]

The jets have tiny openings..
​Grain of sand size could be all it takes..

​If you have the same problem later, loosen the tank cap and leave it loose so air can get in.. See what happens..
​If that makes it run good for a long time, but cap on tight problem returns, then you have a venting problem..

​Worst case (if a venting problem) Loosen tank cap, and run again.. to get to shore.. lol

 

[jimwalt]

The jets have tiny openings..
​Grain of sand size could be all it takes..

​If you have the same problem later, loosen the tank cap and leave it loose so air can get in.. See what happens..
​If that makes it run good for a long time, but cap on tight problem returns, then you have a venting problem..

​Worst case (if a venting problem) Loosen tank cap, and run again.. to get to shore.. lol

Sounds good.

I just read about the new plastic tanks that are out these days don't vent due to the EPA requirements. Mine doesn't either (that I know of), yet it does whine from time to time (or moo like a cow) when it's really under pressure. I'm going to play with it and just make sure before going out to release all the pressure in it and see how that plays out. It did work all summer without a problem till this last weekend, so I suspect the jet just might have been the problem.... I guess.

Who knows? It's just crazy when your at full throttle and then the boat slows down to 1/2 speed out of the blue.

I might go out tomorrow after work just to give it another test drive. I'll report back what happens.

 

[oldboat1]

What happened re. the t.stat? Did it test out OK? (I find the thermostat gasket on that and some similar models is a little tricky -- or rather, a little tricky to reassemble the cover with no leakage.)

 

[jimwalt]

What happened re. the t.stat? Did it test out OK? (I find the thermostat gasket on that and some similar models is a little tricky -- or rather, a little tricky to reassemble the cover with no leakage.)

Since the other stuff worked I didnt mess with the t-stat. You still think I need to?

 

[oldboat1]

Nope. Not if temps are good. Just curious since you had pulled it out....

 

[jimwalt]

I ran it for almost 90 minutes, a lot of the time full throttle with NO PROBLEMS! Must have been that jet I'm guessing. Thank you everyone for your help!!!!