issues with older 70 evinrude

[jeffywestcoast]

boat ran awesome in the yard , runs good at dock, leave dock pinner and it jumps up out of the whole then boggs down once it reaches speed after about 20 seconds, does not respond to squezzing ball to try n pick up speed when it boggs down, fuel pump?? carbs?? or High speed stator??? Trendsetter told me to try squezzing the ball when it boggs down which it did not respond to by picking up revs.. but when i adjusted the adjustment screw on fuel pump at full rev lashed to the dock it was picking up and droppin off rev... i wonder if it has too do with the carbs cause i tried three different fuel lines and eveyone of them when the motor is at full revs the ball is only 2/3's inflated even though it is not sucking air it almost seems like the carbs are not keeping up to the fuelpump...and No i didn't forget to open vent on tank..even tried two tanks and same thing....MUTTHERFUGGER.... any idea's people?, i have 3 of everything but do not want to go changing everything to try and deduce problem.

 

[sparkyew]

Sounds like maybe it is something with the float in the carb. Maybe it has a whole in it and the float bowl runs out of fuel. or if the float level is off..

 

[jeffywestcoast]

ya i think if there was a hole in the float it would be over fueling , but wouldn't that make it continuously be filling the carb? not running it empty?, plus there is three carbs so chances are all three are not screwing up at same time,been pickin my brain all day, i am leaning towards weak fuel pump and it cant keep up under full throttle and the bowls get sucked empty because once i return it to neutral it runs fine. it will idle all day long and it takes off out of the hole but then boggs out 20-30 seconds later.

 

[burnsy22]

I know nothing about engines, (just wanted to get that into the open before my comment in case it doesn't make sense.) When I bought my boat we had a a similar issue with the main (2001 carbed yammy 150hp salt water series). When we did the test drive the motor would almost shut down after 20-30 seconds of running, and the ball wouldn't stay hard. We continually had to pump it in order to run. When it went back to the mechanic it turned out he had left the bleeder valve open on one of the carbs (or all of them) when he had done maintenance on it the day before i took it for a test drive. It was as simple as that. I doubt that is your issue but I thought I would throw it out there.

 

[sparkyew]

It sounds like maybe one cylinder is cutting out. Could be simple as fowled plugs or something electrical like a coil. It's hard to troubleshoot without tests and knowing full history. Even if one carb was mid adjusted and was running out of fuel your down 1/3 power. Did you measure the primary and secondary restiance on the three coils and compare. Are they new plugs?

 

[jeffywestcoast]

nope , i never did any resistance testing on the coils, plugs looked fine but were not new, i just bought this motor used on friday and put it on the boat, it ran fine in his driveway, he seemed honest enough, he said it ran fine, i have lots of coils but dont think that is the issue but cant rule it out, with it running at the dock when i take individual plug wires off i can here a noticeable difference which tells me it is running on 3 cylinders, i will put new plugs in it tomorrow and see if it helps. Thanks Burnsy22 i will check that in the morning, when i hit full throttle it boggs but immediately then power returns when i pull throttle back to 1/3, still i think it is the fuelpump.. but will try and rule that out in the morning. thank for the advice Sparkyew will test the coils individually tomorrow as well after i look up what resistance they should have..

 

[Barnacle Bill]

Are you using a portable fuel tank? Could be just the vent valve not open. ......BB

 

[jeffywestcoast]

nope tried two different tanks.. and 3 different lines.. same thing with all of them.

 

[firelight]

When I had a 90 evinrude it had an issue that it would idle fine then when you hit the throttle it would bog down, took it in to the mechanic and he said the high speed jets in the carb were clogged. He cleaned then out and it worked fine after that.

 

[jeffywestcoast]

i think that's what it might be too Firelight, think it sat for awhile so that will be what i try next, i even have three other carbs from my most recently running 70, Thanks firelight i think you might hittin the nail on the head there, we lashed the boat down to the dock and tried revving it and that is when it messed up as soon as it get to full throttle, back it off again and motor responds.

 

[Roofus]

My Jeff I've got a 70 Johnston and had to fix about everything ill pm you to get more details on your engine

 

[jeffywestcoast]

Also guy i bought it from said he mixed it 100/1 with really good oil, i mix 50/1 with good oil, could this be the problem? as far as i know it is supposed to run 50/1

 

[trendsetter]

Also guy i bought it from said he mixed it 100/1 with really good oil, i mix 50/1 with good oil, could this be the problem? as far as i know it is supposed to run 50/1

Absolutely not 100:1. Never run anything other than 50:1 in this motor. As far as oil type any TCW3 rated nmma certified outboard oil is what this motor needs.

 

[trendsetter]

The problem you are having is almost certainly fuel related. Next step should be to pull the carbs off (it's really easy on these motors) and thoroughly clean the bowl, jets, passages. If the float is set incorrectly (too high) then you can get what you are experiencing here. The float controls the amount of fuel that is allowed into the carb bowls. If the float is too high then enough fuel gets in for it to run at idle but not enough for it to run full throttle. So you gun it, it burns off the fuel in the carb bowls then bogs down until you return to idle when it can keep up.

If you can pump the ball when it's bogging and it doesn't speed up then it's not your fuel pump. Pumping the ball basically overrides the fuel pump as you are manually forcing fuel into the carbs.

 

[GLG]

You might want to try changing the fuel line connector on the motor. Had a similar problem on an old kicker and that fixed it. Don't know for sure but the fuel pump should be easy to inspect for a pinhole leak and if it has a inline fuel filter that might need replacing.

 

[jeffywestcoast]

I have changed plugs , fuel pump is not issue as pumping the ball does not pick up the revs, i checked eack bowl screw to see if any **** came out, spark is not the issue unless it is the highspeed stator,but i think trendsetter knows so i am going to try again , i went back to boatlaunch and lashed boat to trailer and it still boggs out only way it picks up revs is if i move primer switch, same as choke , guess it has to be the carbs..

 

[eaglemaniac]

Hey Jeffy, have you tried spraying in a carb cleaner. I know it's not the greatest idea but it has been known to work. eman

 

[Roofus]

The problem you are having is almost certainly fuel related. Next step should be to pull the carbs off (it's really easy on these motors) and thoroughly clean the bowl, jets, passages. If the float is set incorrectly (too high) then you can get what you are experiencing here. The float controls the amount of fuel that is allowed into the carb bowls. If the float is too high then enough fuel gets in for it to run at idle but not enough for it to run full throttle. So you gun it, it burns off the fuel in the carb bowls then bogs down until you return to idle when it can keep up.

If you can pump the ball when it's bogging and it doesn't speed up then it's not your fuel pump. Pumping the ball basically overrides the fuel pump as you are manually forcing fuel into the carbs.

this most likely the problem I had three carb kits done at marine shop and it was as good as new

 

[Seafever]

Dirty fuel filter? Dirty enough that it will let gas through at lower rpm but not at high rpm?

Put some Injector Cleaner in with your gas (even for a two stroke).............I put some in every tank...along with Fuel stabilizer. That way if the motor sits for awhile with residual gas in it, it won't gum up as fast.

 

[trendsetter]

only way it picks up revs is if i move primer switch, same as choke .

There you go, it's the carbs. These motors have an electric primer that injects fuel into the intake manifold bypassing the carbs. Bypass the carbs and it works then you've found your problem.