1973 Johnson 65 hp STALLS WOT?

[GuttaFixIt]

Hi, I just signed up for this forum and I can say I will love this site. I bought a boat with a 1973 Johnson 65 hp triple on it. Sat for a year (that's what the owner told me). He also told me it ran great. LOL LIVE AND LEARN I GUESS. I got it home and started it. Didn't run the best and wot it stalled in the water. I cleaned the carbs. and it ran better. Still stalled wot. I took it to a dealer and he adjusted the linkage and said he check the carbs. Told me it was fixed. I got it back drove 1 1/2 hours to camp and put it in the water and GUESS WHAT. WOT stalls. I called him and he NEVER took it off my trailer to try it WOT in the river. I WAS steaming. lol I did notice it started PERFECT and the linkage was PERFECT. I didn't have no more play in the throttle. If I wanted a motor to troll with this motor would be perfect. LOL BUT when I put it in the water at WOT it stalls. I also put a new fuel pump and lines on when I had the carbs off. I checked the gas tank (intake) and none of the gas lines are pinched. Does any1 know what it could cause this? Someone told me it could be the head gasket. I am going to check the compression in all 3 cylinders. I have an parts catalog and LOVE working on small engines. So looks like I get to GET my hands greasy. Any HELP would be appricated. TYVM

 

[samo_ott]

Re: 1973 Johnson 65 hp STALLS WOT?

Welcome to iBoats.

As you buy more boats and engines you'll realize they all say they used to work, Sigh.

Anyway, all engines that have sat a while usually have gummed up carbs. You say you took em off, but did you rebuild em? If not, rebuild em. Clean out the old gummy fuel. And also changing the impeller is a good idea on a boat that's new to you.

There's a thread on this forum called "waking a sleeping outboard" or something like that, read it also, lots of good info there.

 

[GuttaFixIt]

Re: 1973 Johnson 65 hp STALLS WOT?

I sprayed carb cleaner into every hole I could see. And blew them out with my air hose. Think I'm going to take them off again and this time get a carb repait kit and try that. If I do then it would be 1 less thing it could be if that doesn't fix it. Thanks

 

[tashasdaddy]

Re: 1973 Johnson 65 hp STALLS WOT?

sound like you did not remove the high and low speed jets to clean them. special tool . i made mine with my belt sander.

 

[Benny1963]

Re: 1973 Johnson 65 hp STALLS WOT?

my 50 1972 johnson was doing the same rebuilt carbs new fuel lines .
fresh gas and timing set it was slighty off .
and choke adjust, it runs perfect now. carbs are critical must be spotless
good tank also.
bennyb

 

[WTL]

Re: 1973 Johnson 65 hp STALLS WOT?

I'm in the same exact boat right now. 64 Evinrude 60 horse stalls at WOT. I broke down the carb and sprayed it with carb cleaner then air, put it back on and its slightly worse (havent done the best job adjusting the slow and highspeed jets.)

Tashasdaddy, I removed the highspeed needles on the carb. I have seen you talk about that tool, and I saw no place to use it so I'm assuming I didn't do what you are suggesting. Are you talking about those 2 brass fittings that are surrounded by o rings that fit underneath the venturi's? Should I bother to break it down and redo?

 

[iwombat]

Re: 1973 Johnson 65 hp STALLS WOT?

The high speed jets sit behind a threaded plug. Besides removing those and cleaning behind them, I'm also a firm believer in dunking the whole carb assembly and all the parts in carb chemical dip. Dip typically come in 1-gal buckets. You can get it at the auto parts store.

 

[tashasdaddy]

Re: 1973 Johnson 65 hp STALLS WOT?

the high speed jets are deep behind what looks like a drain plug on the bottom front of the carb.

 

[GuttaFixIt]

Re: 1973 Johnson 65 hp STALLS WOT?

I have the carb break down and I don't see a low and high speed jets. On the bottom of the carb in the break down I see Orifice plug, washer and screw plug. I am going to buy a carb kit and rebuilt all 3. I'm not sure if the orifice plug, washer and screw plug comes with it. If not I'll have to buy them seperate. I'm not sure what they do but it must be something important. lol

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

I have a 70 hp 1984 and had the exact same problem.
Rebuilt carbs, checked timing, did link and sync.
All of those things helped but it always wanted to hesitate and stall on WOT.
But I then started to question the mixture at 50 to 1.
The bottle says to use 16 oz to 6 gallons and I was using that.
But doing the math

6 gallons is 768 and using 16 oz is 48:1 which means my motor was running lean on fuel and rich on oil. Lean on fuel will cause the motor to bog down on WOT.

So change your mix to 15 oz to 6 gallons and you will be running at 51.1:1
which will not hurt the motor and give you a rich mix of more fuel to less oil.

Always measure the oil with a measuring cup and be right on the mark.

This completely solved my problem by the way.

Good luck
Kyle

 

[samo_ott]

Re: 1973 Johnson 65 hp STALLS WOT?

Huh? That's backwards. 48:1 is richer than 50:1 and 51:1 is leaner than 50:1. It's a ratio, not a percentage. But nevertheless, they're all so close I cant see that being the issue...

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

Samo,
most people get confused with the whole ratio thing.

When you add more gas to the mix you are getting more gas to the engine. Thus it is richer in fuel than on oil.

Thus 48:1 mix has more oil in the mix 48 parts gas to 1 part oil and is a leaner mix of gas and will cause a motor to hesitate and bog on acceleration (not enough fuel)
The 48 is gas the 1 is oil

At 51.1:1 you have 51.1 parts gas to 1 part oil. More gas to burn when the butterflies open up. Your motor does not burn the oil well at all

Rich is defined as to much fuel. Lean is not enough fuel.

Thus 40:1 mix is a lean mix and 100:1 is a rich mix
When speaking of lean of rich only speak of the fuel be it gas, jp7, jp8, ect. The oil is a dilute.

You can richen the mixture by adding less oil.
Kyle

 

[GuttaFixIt]

Re: 1973 Johnson 65 hp STALLS WOT?

When I bought the boat it had a brand new prop. My friend had a 35 hp motor giving to him. He cleaned the carbs and used all day Saturday with no problems. Sunday he went out and started it up drove around the lake and came back and shut it off. He went to start it back up 5 mins later and wouldn't start. Pull start. He took it to a marine shop. Had it fixed for 65 bucks. The shop told him his head gasket was gone and 90% of the time when a head gasket goes it will start, troll fine but when you have WOT it bogs right down and if you keep it at WOT it stalls. His was in the 10%. He told me about this. Just wondering if anyone else heard of this? I'm going to rebuild carbs first. 30 bucks per carb. 100 bucks gone there. LOL Try the ratio. And if that doesn't help then the head gasket i guess. THX for all the input.

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

Check the compression first before ever taking it to the shop.
Autozone should loan you the compression tester when you buy some plugs if you ask. I think that the minimum compression for the 3 bangers is 100 PSI with each cylinder at 15% of each other.

I think that new the compression was 150 psi.

These motors are a very good design and normally do not have to many compression problems except if they have been over heated.

One thing to remember about an outboard is that the carbs do not have accelerator pumps on them like cars do. An accelerator pump squirts a little extra gas during take off to stop the hessitation or "BOG" when you give it gas.

A few things to try to see if it is a lean condition at the start of WOT.

1. Can you ease into WOT (meaning taking 20 seconds or so of slowly increasing the throttle) ?

2. Can you choke the egine as you ease into WOT and the motor get to WOT and then open the choke? If you can, then again lean condition at acceleration.

Do the carb kits. link and sync.

I like to set the idle on muffs in the driveway where the prop spins just fast enough where you can see the ears when not in gear. About 1200,
then fine tune on the water.

Also my motor likes to idle on the water at about 900 to 950 not the 750 the book says.

By the way when you ease into the throttle don't ease it into gear. Put it into gear with authority then ease it into WOT.

Good luck
Kyle

 

[GuttaFixIt]

Re: 1973 Johnson 65 hp STALLS WOT?

When I first got it I went to the lake and slowly put it to WOT and it bogged then stalled. I tried it again and chocked it in and out. If I remember right it took off once for a couple seconds then wanted to stall. I'll check all replies I got. Hopefully I'll be able to fix it. Thx

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

If you can work it to WOT with giving extra fuel:

1. High speed jets need to be cleaned, I don't know if yours are adjustable. Mine are fixed jets (Adjustable have a needle and a seat, one set for each carb) If you ahave adjustables gently screw out and clean then screw back in gently until seated then turn back out 3 turns and try on the water. Adjust as needed

2. Fuel Pump uses a diafram that could be leaking and not pumping fuel fast enough. (symtom; motor will idle and start to take off when giving throttle but dies very quickly as the fuel level in the bowls drops and the motor can't pick up fuel *thus lean condition again.

3. Fuel line pressure not holding (leaking)

By the way two strokes like to run rich and sloppy.

Good luck
Kyle

 

[GuttaFixIt]

Re: 1973 Johnson 65 hp STALLS WOT?

Have you ever heard of a head gasket doing this? I bought a brand new fuel pump. I think I have heard that it has the set jets. After I cleaned the carbs the first time I haven't been able to get it to WOT with chocking it again. I know it starts right up and trolls perfect. When I push the throttle down slow it bogs and then stalls if I don't let off of it. Just wondering if you have ever heard of the head gasket doing this?? Thanks

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

I don't think it is a compression issue. If it was then I don't think that it would idle worth a darn and be very hard to start.

Clean the carbs / rebuild.

Kyle

 

[kynolan2183]

Re: 1973 Johnson 65 hp STALLS WOT?

One more thing how did you set the floats?

They should be even with the carb body when you hold the carb upside down.
And level.