# 90 HP Evinrude Power Problem



## Homfixr (Mar 6, 2010)

I have a 1998 Evinrude 90hp Model # E90TSLECM that falls on it's face every time you apply the the throttle under load. It will rev just fine hooked up to the hose but in the water will only idle and dies if you give it the throttle even real slowly. The carbs are so clean you can drink out of them. Probably not synchronized but they have to be close as it fires up 1st try. Been trying to do some research but everywhere I look I get different answers. I know without physically being in front of it you can only guess but maybe I can get a little more definite answer as to what the problem might be and possibly the correct diagnoses for the problems. I consider myself quite mechanical as I can rebuild car engines and fix most things on cars. Being retired and on a fixed income I need to try to figure this out myself and will take it to a boat mechanic as a last resort if I can't fix it. Thanks in advance for any and all replies. :notworthy:


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## Barnacled (Oct 5, 2014)

Following.


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## Deep South (Oct 8, 2007)

I would start off with the fuel supply. Could be something as simple as the primer bulb. Maybe hook it up to a different fuel tank to verify.


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## oldflathead (Oct 3, 2007)

I have the same engine on my 22' Panga. With 2 people, 40 gallons of fuel and fishing gear it will do 34 knots. 
I would check fuel supply; how old is the fuel? I pump old fuel from my boat tank through a water trap, filter and burn it in my old Chevy van. Then I get new, 100% gas, -NO Ethanol. I have disabled the VRO, (Very Rapid Overhaul) and mix my own fuel 50 - 1.
Have you checked the fuel filters? How about the fuel lines, are they in good shape, not collapsed. How about the fuel pick up inside your tank? I have had one develop a pin hole leak and not allow enough fuel. 
Have you tried a 6 gallon remote tank? If not, I have one you can borrow.
It does not sound like an electrical problem, but ... How old are the spark plugs?
Good Luck & keep us posted.


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## Homfixr (Mar 6, 2010)

I run mine off 2 six gallon tanks that came with the boat. I have had the boat for 10 years and have changed the fuel line only twice. I always got a complete fuel line bulb included. I have only run clean new ethanol free in it. If the fuel is older than 6 months I change it and like oldflathead... run it in my van. I have recently replaced the fuel filter. The VRO was disabled when I got the boat by the way is a 17' Whaler and that motor will push that light boat along at 51mph according to the GPS on a smooth day that is. Before I resort to some expensive mechanic bills I will buy a new tank and complete fuel line. Out of all the results this seems to be the only thing I haven't checked and considering 2 people here right off the bat said the same thing it will be a good place to start. Compression is within couple of pounds so that is good and I just got a spark tester but haven't tried that yet. I will try to post the results of the new tank. This test might take a couple weeks to run as I said before on a tight budget here.:thumbsup: THNX for the replies and will check back soon!:thumbup:


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## kanaka (Oct 3, 2007)

Would like to know your reasoning for the new tank, that's $$$ you can spend elsewhere. Have you put in new plugs yet?


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## floater1 (Oct 31, 2007)

Did you clean the high speed jets


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## Homfixr (Mar 6, 2010)

Reasoning behind new tank is that even with a complete new line with ends and bulb, these tanks which are well over 10 years old, the bulb would get hard but over a short time especially when I stop to fish the bulbs would be soft again. Thinking back on the reason I bought new lines in the first place maybe the tank pickups are worn out, leaking or have a pin hole in them might just be the cause of the soft primer bulb. Something not holding pressure. But even as this happens the motor used to run flat out if needed. Not sure what a high speed jet is but sounds like the jets in the carb which are brand new that came with the kits. Yes new plugs were installed and gaped to specs last year but didn't help either.


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## Floridaboater (Aug 25, 2016)

STOP CHAsing problems with money. Run it off a 6 gal gas tank with new fuel line ans if that works irs ur fuel tank... i bet tho its either your stator or coil packs gone back. Check your spark. Sounds like youre only get spark on some of the cylinders or weak spark which would mean stator


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## kanaka (Oct 3, 2007)

Your compression readings are within a couple pounds of what? What was the reading?

Are you sure you put in new jets since you don't know what a high speed jet is? You could have replaced the float seat.

Plus, you can get new parts for the gas tank if needed to rebuild but the motor should run off whatever is in the float bowl for awhile, think about it.


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## CurDog (Nov 14, 2010)

When in the water, do you get any distance at all when you give it throttle, or does it die immediately when you throttle? If it dies immediately, I'd think it's the low-speed jets clogged. If you didn't mark the carbs (1,2,3, or Top, Middle, Bottom) when you pulled them, then they are most likely out of sync, unless you have good memory. 
-If you give it throttle, and you're getting up in speed, then nail it (WOT), then power slows and then dies (it'll usually stay running if you back off the throttle fast enough), it's most likely from sucking air from the line, bulb or tank gauge gasket causing an interruption of fuel flow. Or you forgot to open the tank vent. 
-If you're running the motor at WOT but not getting it, and the motor is trying to open up, rpm jumps up high then drops down continually, then it's a high-speed jet clogged. 
I have a tank you can borrow to check your tank/lines if you want. I'm in Milton. Just pm me.


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## Ocean Master (May 20, 2008)

Let Floater1 take a look. He is a wiz on these motors. I had a 90 myself and its perfect. 45 mph on a 17’ Aquasport


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## Homfixr (Mar 6, 2010)

The kits I bought had jets in them. I did this last August when the problem started. I did one carb at a time. Even the jets I took out were clear but I put the new ones in anyway. Did Not solve the problem. Dies just as soon as you hit the throttle while in the water. Hit it fast or slow it dies! Thnx for the offer CurDog and I will keep that in mind the next time I can take it out. The wife not feeling good and been the hospital for 9 days now. Going to take a while to recover from this one physically and financially. Before I spend money I will ask you if your offer stills stands. One thing I can do is the spark test once she comes home. I will post those results when I know them. Now yall gone and confused this old man with all the different problems it could be. Prolly going to have to take to a mechanic in the end but I wanted to try to fix myself because that is the way I am. I believe it is called Jolly Rogers Marine at the corner of Pace and Garden/Navy Blvd which is real close to my home and I understand he is fair and good. Unless y'all tell me different I believe he is a member here too.


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## CurDog (Nov 14, 2010)

The only other things I can think of is if your engine has the single power pack, it has the OIS (optical ignition system), which "requires" the QL77JC4 spark-plug gapped @ .030". 
Problems arise because people like NKG plugs and not knowing this engine can and will shut down (power kill) in wot if using different plugs. 
Or you are getting a positive charge running thru the Blk/Yel (may be Brn/Yel, it's been awhile. pretty sure it's the Blk/Yellow tho), wire at the key switch, causing it to short out and killing engine power (the higher you rev the engine, the more volts are created). If this is the case, there is another short somewhere causing the positive to merge into the neg. side. 
I'm sure you could google it to find the most common source where the short would occur.


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## CurDog (Nov 14, 2010)

I'm working on a 48spl right now, bad primer solenoid. But got me thinking, if your carb floats are too far out of adjustment, it can allow only enough fuel to idle and maybe putt-putt, but as soon as you hit WOT, the engine sucks the little bit of fuel out of the bowl, then the engine starves for fuel and will shut down. 
And as you describe it runs fine with rabbit ears (under no load), but in the water (being under a load), it'll shut down. I believe what's happening is since the fuel demand will be greater under load, the carbs are not suppling enough fuel to sustain that need. No fuel = shut-down. 
I've had them before where the engine would die or run really rough when the motor was trimmed up running WOT. Problem (on that particular motor), was the middle carbs' float out of adjustment. Once it was re-set, it purred. g/l


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## Homfixr (Mar 6, 2010)

Thanks CurDog. I am definitely going to change the plugs as mentioned above and if that does not solve the problem in my mind not a waste of money as new plugs never hurt. I can go back and reset all the floats. I believe I did them to the specs I found online but that was a year ago. The boat has been sitting that long now because of too much work but this is fix'n to change! As I explained before may be some time before I can check the advice given but it going to happen soon! I will update this post at that time. Again Thanks to all and happy fishing! :notworthy:


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## Ocean Master (May 20, 2008)

Of subject bit I had an 88 Special Selectra Shift. It has electronic shifting by push button. It was a breeze to hold the boat still. Kinda like the old Dodge push button shift.


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## Homfixr (Mar 6, 2010)

Sorry for the long delay but had some personal problems arise. I finally took it to a mechanic in Mississippi that owed my daughter big time. He did $1600 worth of repairs for $780. It had a blown head gasket so he had both heads reworked and a lot of new gaskets. He went through the carbs but found no problem there but adjustment. He changed the plugs to specs. He check the water pump and it was good as it was almost brand new before the trouble started. Thinking back I got some seaweed wrapped around the water intake and it ran hot. I shut it down as soon as the alarm went off but that prolly started the whole mess. Any way Thnx for all the advice and now just waiting on my brand new Hummingbird 698CI HD SI dead out of the box to be returned to me from Hummingbird so I can go fishing again. Brand new to the waters around Pensacola so I will be asking for a little advice as to where to start once I get the 698 back. Again THNX everyone for your input.


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