1981 Rude 90, wont go over 2k rpm under load....any ideas?

[Corjen1]

Hey guys, new here on the J n E forum, spend a bunch of time in the dry dock one though.....

Anyway, here is my question/questions.....and back story.....dealing with a 1981 Evinrude 90 hp. The motor has had some kind if fuel issue since Ive had it.... will run great, until you turn it off, say to anchor and swim or something. then it will be a bear to start., Once started, it will hesitate off idle, like it is either choking or starving for fuel. once past that, it will clear out and run great again. Last fall, we had been playing all day, we had beached for several hours and then it absolutely would not start again, period.

fast forward, he last couple day Ive been dinking around, un-pickling it from the winter and such. It was some what difficult to get started, but I this was the first time ive ran it since fogging the cylinders last fall. I did put new plugs in, as I do every year, gaped to .030 running on muffs, I noticed a sporadic cough or mis, would happen every 30 to 45 sec, regardless of RPM.

Took it to the little lake near our place, again difficult to start, with the warm up lever, it would go to at least 4500 rpm, I dont leave it there, or let it go as high as it could with the lever, but under load ( in fwd gear) it would only get to 2000-2100 rpm nothing more......would even come on plane....

Tomorrow, I will do a compression check and spark check....anything else I should go after? Any insight will be much appreciated!!

Thanks, Cordell.

 

[Bosunsmate]

If any of those small bypass hoses or valves get clogged it will run like that.
the ones i mean are the ones that go from the bypass covers to the little valves around and under the carbs,
if they have a tear you wil have problems too
check how the plugs look too, are they dissimilar?
i always pull off the top plugs leads and then reverse that on the bottom plugs to check both top and bottom carbs are working

 

[Bosunsmate]

the starboard bank pistons i find overheat on these.
the waterdefectors go and the thermostat housng has a weakness in its design too, a little hole can block up and that stops thermostats functioning properly

 

[emdsapmgr]

Possible the engine is not running on all 4 cyls. When it's hard to start, check each plugwire to be sure it is firing. You can use a spark checker or an inductive timing light. Either works to show spark. That engine will run on only 2 or 3 cyls and sound normal in neutral or when running on the trailer. It needs all 4 firing to make hp when under load. Also, weak ignition components tend to work when cold, then crap out once the engine heats up to normal operating temps. So, check for spark when the engine is well warmed up.

 

[Corjen1]

Thanks, Much appreciated!!

 

[Hooligan Diver]

...

 

[Hooligan Diver]

I just solved the same problem on a 235 v6 (with the help and advice from those here on the forum), it was a fire issue on 2 cylinders. Did the exact same thing you've described. I would have never guessed it to be running on only 4.

 

[81_chapparel194]

to the OP I have the exact same problem exact same engine. as for the hard start. mine will reach wot if I feather the choke by constantly pushing the key in. once I reach 1/4 throttle its perfect from there up. I have found I have an eratic random misfire on one particular cylinder. swapped coils still same cylinder misfire so its not the coil. please update me if you find a solution as will I do the same. I bet we have the same failed part. I have removed and cleaned and rebuilt my carbs at least 20 times in a year and no difference. I am leaning toward a bad stator/or power pack.

 

[Corjen1]

I just solved the same problem on a 235 v6 (with the help and advice from those here on the forum), it was a fire issue on 2 cylinders. Did the exact same thing you've described. I would have never guessed it to be running on only 4.

Hooligan, what was the corrective action? or can you point me to your thread? Thanks...

 

[N1NE1]

Check out the coils,one could be dropping out.Use a timing light

 

[Corjen1]

Results from checks this morning:

- compression - #1 125, # 2 130, # 3 130 and #4 130. Dont believe to to be the issue.

- Spark Check - I dont have an ignition checker so I removed the plug and grounded to the block All 4 cylinders are sparking. Both visually and by feel . I did managed to zap my self a couple times. (Dammit man!!)

- Started the motor, ran for a bout 5 mins on muffs, pulled #1 plug cap, died instantly, reinstall cap. Restarted, pulled #2 plug cap, died instantly, reinstalled cap. Restarted, pulled #3 plug cap, no change (Interesting) reinstalled cap. Pulled #4 plug cap, no change (Very interesting)

Plug check - # 1 and 3 (rt bank) drk brown (rich?) 2 and 4, black and wet. Lt bank cylinder heads not even warm....( they are brand new yesterday by the way)

Summery, if you think Im off base lt me know..... something is up with the ignition on left bank. I know that it is sparking, zapped the crap out of me. But the plugs are black and wet, heads cold, obviously not firing correctly. Im inclined to think the coil packs are toast...But why would both packs go on the same side, at same time?? Is there something else that could be causing one bank to go south?

Think I will get a carb rebuild kit and try to hunt up a coil pack part number......

 

[racerone]

What colour stripes are on the wee orange wires going to the top coils and what colour to the bottom coils ?

 

[Corjen1]

What colour stripes are on the wee orange wires going to the top coils and what colour to the bottom coils ?

Maybe Im not understanding your question, it appears to me both coil packs on each side have the same colors....orange and blue.

RT side:



left side:



from the power pack connector, both coil packs are connected to this plug...

 

[racerone]

I believe post #12 ask a question and is very, very clear.------But try this , figure out a way to reverse the wires on the left side.-------Sparkplug wires / the two wee orange wires / or remount the 2 coils.-------------A simple test for you to do !!

 

[metriccrescentwrench]

What colour stripes are on the wee orange wires going to the top coils and what colour to the bottom coils ?

Maybe Im not understanding your question,

What he's getting at is that the orange wires are color coded for which cylinder they go to. Since it appears that your engine only has 2 cylinders contributing power it's possible the other cylinders are firing at the wrong time due to the wires being reversed. If I remember correctly there's a link in the 'top secret files' thread to wiring diagrams that should show the color codes etc.

 

[Corjen1]

I believe post #12 ask a question and is very, very clear.------But try this , figure out a way to reverse the wires on the left side.-------Sparkplug wires / the two wee orange wires / or remount the 2 coils.-------------A simple test for you to do !!

Sorry, I thought I did answer the question, the orange wires that I could see have blue strips. I posted the rest of the stuff, because the question seemed to indicate there would be a difference in color from top to bottom, and I wanted to be sure if I was looking at the correct orange wires because mine were the same.

Regarding the simple test, are you saying to switch sides with the the "good" side via the plug wires, orange wires or relocating the coil pack? To determine if the problem follows to the right bank?

 

[racerone]

????????????-----Switch the wires on the left side only.-----Or switch the coils !!!!!!!------Not sure why you are not following this at all.---An elegantly simple test for you to do.-------How long have you owned this motor?

 

[Woodonglass]

Hey Racerone... It may seem simple to You but for a rookie DIY'r that does NOT mess with Outboards everyday, it's not easy following what you are saying. He posted Pics to show you what he has. It might be nice to reference his pics to help him understand what you want him to do. That's if you truly want to help him out. Give him a Break!!! Obvioulsly he's not understanding what your are trying to say. What you consider a simple thing is NOT always that simple to a Newb Novice!!!

 

[Corjen1]

????????????-----Switch the wires on the left side only.-----Or switch the coils !!!!!!!------Not sure why you are not following this at all.---An elegantly simple test for you to do.-------How long have you owned this motor?

???????? I dont know why im not following, maybe is something in my interpretation or your instruction. You obviously know about these motors and the info is appreciated, I dont anything about them. Thats why Im asking for help on this forum.

As I said in post 11, both cylinders top and bottom on the left side are displaying the same symptoms. I didnt understand why you wanted me to take switch them with each other, what am I looking for exactly after the switch?

 

[Bosunsmate]

is that a broken orange wire in the bottom photo on the bottom coil