Outboard motor help

[LUCKYDAWG13]

I'm in need of some outboard motor help I have a 1994 30 hp Johnson motor runs fine at lower speeds but at full throttle i have power loss motor does not die but goes right to a idle speed any ideas on things to check out
thanks for your help

[cabezaverde]

I was having similar problems with my 25 HP of about the same vintage. It turned out to need a CDI pack.

[clum553946]

Check out the bass boat central forum, might get some more answers there.

[JonB_in_Glencoe]

maybe fuel pump...hole or tear in diaphragm?

[Winger Ed.]

I'd try the obvious things first, fuel filters- there may be one in the tank too, spark plug wires, electronic connectors,
poor flow through the injectors, etc.

Something I've done every 10 years or so is get a rebuild kit for the engine's fuel pump.
I'm not sure if the modern generation stuff with alcohol in it hardens up the rubber diaphragms or not, but I don't trust it.

[GregLaROCHE]

First thing to check is fuel flow. Start at the pick up in the tank, then fuel lines and finally verify the fuel pump is working properly and there is no place in the fuel system that is sucking air at high rpms. If the problem isn’t there, the carburetor needs to be checked out. After that it’s the electronics part and you will probably need a professional with test equipment.

[Shawlerbrook]

Sounds like a problem caused by the ethanol is gasoline. It is murder on carburetors.

[LUCKYDAWG13]

ok i did find that 2 of the hose clamps on fuel line were lose also carburetor cover screws were a turn lose I have been troweling a lot
this summer and fall would changing spark plug help

hopefully it was just sucking air from the lose clamps I will test out next weekend I just hope its something simple
before i start changing parts out

[farmbif]

sounds like it could be cdi pack with rev limiter gone haywire, if it were carb or gas flow it would never get to high rpms, if coils are going bad they stop making spark when they get hot. are all the linkages the way they should be, check all the plastic balls and sockets to be sure timing base is moving when throttle is opened up.

[GregLaROCHE]

Change the plugs at least at the beginning of each season and always carry a spare set and wrench. Make sure your gas oil mix doesn’t get too rich. It will cause plug fouling.

[megasupermagnum]

I have plenty of ideas for you to try, but before anything. #1 change the spark plugs. #2 clean the carburetor (take jets out, 100% clean them). Before you do those things, you could be chasing your tail.

After that, the problem will be either ignition, CDI possible, but also the ignition advance. Or it could be fuel, which I would lean this way.

There is a very real chance your main jet in the carb is plugged, and that is all that is wrong.

[LUCKYDAWG13]

I have plenty of ideas for you to try, but before anything. #1 change the spark plugs. #2 clean the carburetor (take jets out, 100% clean them). Before you do those things, you could be chasing your tail.

After that, the problem will be either ignition, CDI possible, but also the ignition advance. Or it could be fuel, which I would lean this way.

There is a very real chance your main jet in the carb is plugged, and that is all that is wrong.

I will do these things first it just could not have happened at a worse time The Walleye are just starting to turn on I did pick up a new gas tank that i was going to use next spring may as well use it now

[Winger Ed.]

Old fuel will make them run goofy too.
If the gas doesn't smell new--- flush the tank and change it.

[Adam20]

rubber lines go bad over time or get clogs inside them, ethanol is not kind to them, Had a motor run like that and it was air vent on fuel cap

[Tripplebeards]

Everyone has it pretty much covered. I’d clean the high idle jet first before doing a thing else if it’s carbureted. Then if it doesn’t help start running through the motions and start with checking the plugs and wires. Plugs are $5 bucks each so just replace them. Check all the in line fuel filters and replace the tank with fresh gas with a can of sea foam added. If none of that helps the CDI pack is probably your issue. I’m guessing you just have a clogged high idle (main) jet. I wasted a lot of time to find out my CDI pack was bad on my 93’, 20 HP Mercury a few summers back. I messed with a lawn mower this past spring that the jet was clogged like it had been cemented shut. A sowing needle and compressed air took care of it. Just grab a Chilton’s manual from the library if you need help.

[tomme boy]

Where in Il are you? CDI on these motors is rare to go bad. Coils do. When you say it goes to idle at high speed, care to explain more? That is not saying what it is actually doing. Does it increase rpm then starts to bog or does it start missing? If you had a video it would be a lot easier to see.

Fuel pumps are notorious on these motors. Takes about 5 minutes to change. Very easy right on the side of the motor.

[Tripplebeards]

Tommy, I forgot about coils. You can normally tell a bad coil if the motor runs fine when it’s cold and then starts to miss when it heats up. Motorcycles do the same. If it’s bogging right off the start on a cold engine i would probably rule out a bad coil. Easy way to test just like plugs and wires is to unplug each one while it running to see if it runs worse or the same. Just wear gloves when doing so.

[LUCKYDAWG13]

Where in Il are you? CDI on these motors is rare to go bad. Coils do. When you say it goes to idle at high speed, care to explain more? That is not saying what it is actually doing. Does it increase rpm then starts to bog or does it start missing? If you had a video it would be a lot easier to see.

Fuel pumps are notorious on these motors. Takes about 5 minutes to change. Very easy right on the side of the motor.
Ok if I'm just trolling motor runs fine if i go to half Throttle runs fine if i get on plane and back off on the throttle runs fine full throttle its like someone just turned the dimmer switch to low but if i sneak up on it it will run for a little while until power Loss
And I'm in McHenry county

[megasupermagnum]

Ok if I'm just trolling motor runs fine if i go to half Throttle runs fine if i get on plane and back off on the throttle runs fine full throttle its like someone just turned the dimmer switch to low but if i sneak up on it it will run for a little while until power Loss
And I'm in McHenry county

Do as I stated above, then next time you take it out try pumping the bulb as you are going full speed. If you pumping it fixes it, you have a bad fuel pump. Don't try and save money buying the rebuild kit. Buy the whole pump.

[Winger Ed.]

but if i sneak up on it it will run for a little while until power Loss

Sure sounds like a fuel flow/delivery problem.
A clog, the pump, sticky float if its not injected, dirty filter, semi-clogged jet, something like that.

[megasupermagnum]

It is carbureted. Johnson was always the no-frills version of Evinrude. I believe they were carbureted right up until they were discontinued 10 or so years ago.

[popper]

O ring in the fuel line at tank or engine.

[LUCKYDAWG13]

I will start checking things out new spark plugs will be going in I do have a new gas tank and will clean the carb will let you guys know
how things go over the weekend thank you for all the tips and suggestions

[Jsm180]

I had an Evinrude dealership for 15 years in the 70's 80's. First pull the plug wires off the plugs and rotate the flywheel by hand to check for compression in both cylinders. If good pull the sparkplugs out and plug them back into the boots, rest them against one of the head bolts without paint and spin the flywheel either with the rope or starter if equipped. You want a nice blue spark, if it isn't replace the plugs. If you have spark and compression, pull the carb and clean it, it is likely the main jet is clogged but there will be crud in the bowl that can"t be cleaned without disassembly. Beware, simple fixes can get very expensive when performed by someone with less than adequate talent.

[Tripplebeards]

Make sure there is a proper seal from your fuel line going from your tank to your motor as well. Like others said check your bulb. First thing I’d do is get a can of sea foam and run it though your tank. If it’s a dirty carb the odds are it will clean out with sea foam. I would say after 15 to 20 minutes of running on average. I’ve ran sea foam though my ruff running outboard many of times and within 20 minutes what ever clogged the carb blows though. After a half hour to 45 minutes of running with sea foam and it still runs ruff it’s time to dig further. I had a small pebble of sand in a SeaRay few bowl once that kept clogging the system. I had to drop the bowl to find and remove it. After I did all the things I mentioned on my 20 hp Mercury and it still killed at higher speeds I took it in for repair. It turned out to be the CDI box. Would run fine and start right up but as soon as I gave it throttle it acted like it was running on one cylinder.

[popper]

Don't forget to open the tank vent. When OMC owned, johnson and Evinrude were exactly same but the cover. Check valve in priming bulb or O rings in connector lines get damaged. My 65 had the same problem, Ok at idle and above but bogged at full. Got towed to the bait shop and they had replacement O ring. Problem solved. Sounds mostly like a fuel problem, OMC buddy always recommended running it dry after use. Worse problem is when you're skiing and the one piece handle breaks in half.

[metricmonkeywrench]

As was explained to me a long time ago, with boats the rules of the game are a bit different. The suck-squeeze-bang-blow process remains consistent, except in the case of boat motors they are under 100% load at all times when in gear. What would be a minor problem often unnoticed in any other application is magnified in a boat. As such all the components and systems have to work within tolerances to meet performance and it doesn't take much to knock it out of whack.

I'm with the crowd, sounds like fuel and/or ignition

[LUCKYDAWG13]

I always run gass out of the motor i always disconnected the fuel line and let run until out of gass

[tomme boy]

Be careful if the new tank you have is the new unvented kind. They will flood out most older motors is the needle and seat are marginal. They keep pressure in the tank and that will force gas into the carb and can flood the motor.

Sounds like the pump has a hole in it. Skip the Seafoam it is just ethanol in a can. It can make things worse as it will break up everything in the system. One other thing you need to be careful of is the GRAY fuel lines. The liners in them are junk. They start to break down the very first time you use them. Use regular fuel line from the auto parts stores. It does not matter who has the gray fuel lines, they are all junk.

[MaryB]

Ethanol makes the inside of the fuel line swell up and restrict flow if the fuel line is old... I used to replace fuel lines every 4-5 years, UV hardens them up, the ethanol eats them... granted mine was the portable tank setup and the fuel line was exposed to the sun all winter...

[bdicki]

I've had the same problem on a newer Yamaha and it was water in the fuel filter.

[megasupermagnum]

I've had the same problem on a newer Yamaha and it was water in the fuel filter.

I've never seen water in fuel cause only a full speed issue. It almost always results in rough idle and misfires. As for tank pressure problems, if that were the case it would cause flooding (no start), or running very rich. He has the exact opposite problem. My opinion, and that is all it is, is that Seafoam and other dump in cleaners are a waste of time. I've yet to see them actually do anything on any problem I've seen them used on. A proper carb cleaning with a carb cleaner is the only way to go. Definitely remove the jets, and I recommend cleaning in B12. A generic carb cleaner in a spray can works too. Do no waste time on any "carb dip", they don't sell anything that works anymore. A bad quick connect fitting on the fuel hose could do it too. You will know they are bad if you pump the bulb, and gas leaks out of the connection.


FYI, B12 Chemtool is the real McCoy. This stuff will burn you, and will melt nitrile gloves. Be careful with it.

[.429&H110]

+1 what popper said
I vote fuel line, unvented tank, vacuum leak, maybe fuel pump.
Try somebody else's line and tank.
If it works, it ain't the motor.
Been there done that. Ethanol is not your friend.

[tomme boy]

Ethanol actually runs ok in these single carbed motors. Once you get into multiple carbed motors and then they start having problems. My 3cyl yamaha 2 stroke runs like you unhooked a plug wire if you run ethanol in it. Carbed yamaha 4 cycle motors were famous with gummed up carbs as the ports were extremely small.

Best thing anyone can do is get automotive ethanol rated fuel line. NONE of the aftermarket marine line is safe. Even though it says it is. Factory hoses are safe but $$$$$$$$

[Tripplebeards]

^^^I’ve bought cheap replacement fuel lines and bulbs that have collapsed internally as well causing bogging issues.

[higgins]

If it's leaking gas out of the carburetors one of them may be stopped up. I had a late 80s Evinrude in the shop for the first time a couple of years ago when it started doing what you describe. Carburetor rebuild fixed it.

[tomme boy]

Carbs on these are one of the easiest to rebuild. Usually a new needle takes care of most problems. Take a qtip with toothpaste and spin the tip in the seat to polish it. Then blow it out. If that and making sure the emulsion tube and main jet is clear will fix most carbs. Most people do not take out the emulsion tube and clean it. Then they wonder why their motor is still running like poo

[LUCKYDAWG13]

Up date new gas sparkplugs Gas cap and a half can of gumout started out a little rough on full Throttle sprayed a half a can of gumout in the carburetor runs great now so i think it just had some crud in the jets thanks for al the help had a good day fishing too one Walleye 26"270978