1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

[whitetailed]

Hello I Am new to this site. I have a 70HP Evinrude outboard. It has ran great this season. The other day I took it out and at High speed it would bog down and then take back off. It was like I was pulling throttle to an idle, then it would take back off on it's own for a few seconds run great then bog again. Does anyone have suggestions for me. I changed the plugs but no help.

 

[91kuhndog]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

white tail,
I have 4 of these motors... and seen this. If you're running this motor on a 6 gal tank, get a can of Sea Foam and run a whole can with 5 gal gas. You have a carb. gummed up. Basically, you're dropping a cylinder because you don't have enoughh fuel coming from a high speed cylinder. Of do this. Run the motor,....when it drops down like it's doing.....reach down and kill the motor! Pull the plugs out one by one and check to see which one is dry (or really soaked with fuel/oil). That'll be you're problem cylinder. If it's dry, hot, you have a fuel problem, and that cylinder is starving for fuel. If it's dripping with gas, you have an ignition issue and are losing spark on that cylinder. You'll be able to tell by looking at the plugs. Keep us posted!

Brad

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

Thanks Brad I will check this out. I do have a 6 gal tank. Will seafoam clear it up. I tried running a can of carb cleaner through it, no help. The motor idles fine. Could it be the fuelpump? Do you think the carbs need rebuilt? I unhooked the gas line on the inlet side of filter. I started the boat it ran It took like 2 mins to empty the filter? Shouldn't it suck faster.

 

[91kuhndog]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

The Sea Foam will help clean out any varnish that builds in the fuel lines and carbs. (It'll smoke too) I usually run Sea Foan in my rental boats every fall before I store them for the winter. It works to de-carbon the motor too! You might want to consider have the carbs gone through in the future; just don't run the motor to the point where you tear up a cylinder.

YOU KNOW WHAT???? I have a thought..... Sounds like you have water in the gas. Put new gas in the tank, add oil and Sea Foam, and run on that. Also, under the carb covers, on the bottom face of the carb, you'll see a large common screw. That's the drain to the fuel bowl, take it out (hold a towel there to catch whatever comes out), and see if it's clear gas or water. Drain it good, run with the new gas, and try again.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I pulled all the plugs when it was acting up. They all looked the same. None were wetter or dryer than another. When I run the sea foam through it is it all right to let it idle with muffs on?

 

[91kuhndog]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

It is. Let it idle with the muffs on. Just don't rev it up with the muffs on. That is a common mistake and can very easily damage a motor or cause a motor to run away (over rev). Drain the carb bowls though and put new gas in it.....I think you've got either varnish or water in the gas...

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I drained the carbs earlier, it looked like gas, no chunks or nothing, no water neither. I have another tank that I will put fresh gas in tomorrow. I will also put a can of seafoam in it. When I run the seafoam through it should I have the boat in the water and idle around or can this be done in the driveway with the muffs on? I have probably put 15 hours on it this season you still think it could be varnish? I will let you know what I find out tomorrow evening thanks again.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I drained all the gas and put fresh gas in to a new tank. I started the motor and the same thing it started chugging. I sprayed gas mix into the carbs with the following results, top carb stall, middle carb stall, bottom carb the chugging quit but wan't running real smooth. Do you think the bottom carb needs rebuilt.

 

[Brokeback Johnson]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

Since it just started acting up, try blowing out the high speed orifices while the carbs are still on the motor. Quick shot of air is sometimes all it takes. I have done this successfully on a 70 in the past.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

Where is this orface located? Do I need to open the butterfly?

 

[Brokeback Johnson]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

Remove what looks like a drain plug from the bottom front of the float bowl - jet orifice is behind there. Just a quick shot of air through the passage may help. This is no substitute for a thorough carb cleaning but can help in a pinch.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

thanks i will try this and let you know what happens.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I blew air into the orfice and no help. I guess it is time to take the carbs off and give them a good soaking. What should I clean the with? If anyone could give me some pointers that would be great. Great with car engines just havent messed with small engines that much.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

Well today I tore the carbs off, disassembled them inspected and cleaned, and still no help. The boat still acts like it wants to stall at full throttle. If I choke it while this is happening it kills motor no help.. Someone please help

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I am still stumped, new filter, carbs cleaned, new gas, new plugs, and no help. Today I took out the plugs when it acted up. ALL OF THEM WERE SOAKED, Could I be getting to much gas? Or not good enough spark?? SOMEONE PLEASE HELP, 5 DAYS TILL THE WEEKEND OF THE FOURTH.

 

[oakey]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

My 70hp Johnson just started doing the same thing it is an 1987. This is what I have done with no help yet. I changed the fuel filter, put on new fuel lines, put can of dry gas in tank, put stabil for ethonal in tank, tightened all hose clamps, to me it seems like an air leak in the gas line someplace. I have used the boat about 12 hours every week for the last 3 months. So I am ruleing out varnish. The only thing I haven't tried is a new ball in the gas line. That will happen tomorrow. Engine runs great up to 3/4 throttle at 25mph. goes down to about 8mph if I push the gas to wide open. After reading all your posts I know what didn't help you, maybe my tries will help you narrow things down. My boat usually runs at 35mph WOT, I am thinking maybe the filter in the fuel pump might also be the prob. Please let me know if you get yours fixed, and I will do the same.

"Oak"

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I will let you know if I find a cure keep me posted with the bulb.

 

[whitetailed]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I found the problem. I was looking engine over real good today. I found two wires, that had cracks in the sheathing. Not sure what they went to so i fixed them and Boat runs like a champ. Better than ever probably since I replaced and cleaned the whole fuel system. JUST IN TIME FOR THE FOURTH!!!

 

[oakey]

Re: 1981 Evinrude 70 HP E70ELCIH Bogging out during high speed

I changed the bulb today and also the female fitting to the engine when I was putting the fitting back on the motor I noticed the O ring on the male end was missing so I replaced that and the motor ran great. I was back at 35 mph right off the bat. Then it started to do the same thing again bog down and the rpm's droped to about 25 and nothing is better yet. But you might want to check your O rings on the fittings. And let me know if you found anything else.

"oak"