87' 225 Johnson Rough Idle And Loss of Power

[Blake0912]

I was running the boat today and it ran great for about an hour then I let it sit and fired it up and it would not go above 3k RPM like its not running on all cylinders.
Recently I converted it to pre mix and and put a new VRO fuel pump on it. Also I replaced the fly wheel because the magnets were loose and the teeth ring broke off. Then last weekend I did a de carb using sea foam and ever since then it's been idling horrible.

I'm thinking that the fuel I have in the tank is mixed way rich and may have something to do with it. I was not sure the amont of fuel in the tank when I went to pre mix so I put more oil then I should have. Also I will replace the plugs and put in fresh mixed gas tomorrow. And will do a compression test on it , already did a spark test and it's good. On a side note there is a lot of burnt oil/gas coming out of the prob and it never used to do this.

Any ideas of what could be the problem? Thanks for the help.

 

[dehydrated]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Are all the cylinders wet and oily? I would pull all the jets and clean them could of moved some crap around . Have you replaced the fuel hoses?Also are you sure you got the right flywheel?

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Yes all cylinders are wet and very oily. All the fuel lines/water seperator and primer bulb are new. The fly wheel was identical to the original one and matched up with the parts number. I ran it three days last weekend and burned about 40 gallons of gas and it was running fine so I think the fly wheel is okay. It started to run bad after I de carbed it. It's like the motor is loading up and can't clear itself out or the carb jets are clogged. Im about to go do a compression test on it.

 

[daselbee]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Sounds like you are not firing on all cyls. Somehow you lost a cylinder. Check proper firing on all plugs.

 

[dehydrated]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Sounds like you are not firing on all cyls. Somehow you lost a cylinder. Check proper firing on all plugs.

Could be just as simple as draining all the gas out and cleaning the carbs ,compression test might show something but the fact all the cylinders are the same oliy condition makes me think that youn need to run it till all that gas is out and start with fresh fuel and the right mix

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Just did the compression test and it's 90-95 across the board I know that's kinda low but at least it's even. I'm cleaning the carbs now one was leaking fuel when I pulled the air box off and the needle seemed stuck hopefully this will help.
I did a spark test it will jump a good gap

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

I think my problem is the needle on two of the carbs is not seating correctly , I pulled them apart and cleaned everything but when I fired the motor back up the same carbs still had a bit of fuel seeping out of the throught. So Im going to bite the bullet and just order six carb kits and rebuild them properly. Do these motors have high/low speed jet adjustments or are they pre set?

 

[daselbee]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Preset by fixed air bleed orifices.
You are barking up the wrong tree. Based on the description you post, a "bit of fuel seeping" will not caause a loss of power down to 3000 rpms. Now granted, it might cause a rough idle, but not a loss of power at speed.
You have lost a cylinder for some reason. Maybe two.

EDIT: Might be as simple as fouled plugs from the decarb.

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

I was thinking the same thing about it dropping the cylinder and im going to try a new set of plugs. Since the spark will jump a proper gap what else could cause it to loose a cylinder or cause it not to fire? Im going to rebuild the carbs anyway becasue its most likely been years since they have been cleaned and hopefully it will help my idle issue. Can having to much oil in the gas be causing some issues also?

 

[daselbee]

Re: 87' 225 Johnson Rough Idle And Loss of Power

You can run 25:1 oil mix (double oil) and it will not really affect anything....maybe plugs a bit. It will not cause your symptoms.
I found a particularly troublesome cylinder dropping problem by installing new plugs, run it, and then read the plugs.
The one that looks new will be the cyl that is dropping.
Just to be sure, you did check ALL cylinders spark....right?

No QuickStart on that model, so that's not it. You check the shift switch? That will kill three cyls. (Not likely, but worth a check.)
You had the orange wires off the coils? Any chance you swapped #2 and #4 orange wire? Orange/blue=top, orange=middle, orange/green=bottom.


EDIT: Just re-read your original post.....any chance you have a failed temp switch, AND the horns are not working....i.e. it is thinking that it is overheating all the time, and has limited the rpms to safe mode (2500). I know you are saying 3000, but could be just inaccuracies in tach....
It isn't overheating is it? To test, make SURE it is not overheating, and then disconnect the temp switches at their plugs. If problem goes away, AND IT IS NOT OVERHEATING, then you might have a bad temp switch.

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

I considered that it could be a bad shift switch but how do I check that?
Yes I checked all the cylinders for spark twice , the plug wires are going to the correct cylinder. It may be less than 3k but the thing is when I go to plane up it just sounds like its loaded up then I back off the throttle and it goes down to like 400 RPM hesitates for a few seconds then dies. Then it will fire right back up and smoke like hell.

It's not over heating it has about 15 PSI at idle and I can hold my hand on the heads after its been running for a while and it's not hot also the warning horn does work I checked it by grousing the tan wire coming from the head and it will sound off.

I have a feeling it's a fouled plug but they are new , they were in the motor when I did the de carb ( I know I should have put them in after the de carb I was not thinking ). But I pulled all the plugs out and cleaned them in gasoline. But could one still be fouled and not firing even though there new and cleaned up after the de carb ?

I would think that even with one cylinder dropped it would still get up and go?


EDIT : I noticed a whole lot of spent oil/gas coming out of the prop exhaust after running it. Made a couple big puddles in the driveway it never used to do this at all ( it's not gear oil from a leaking lower unit seal ) could this be a sign of a bigger problem?

 

[daselbee]

Re: 87' 225 Johnson Rough Idle And Loss of Power

That oil is a sign that a cyl is not firing or severely misfiring. It can also be an extremely rich condition. You are doing the right things. Try a timing light on each plugwire watching for dropouts or any kind of misfiring by looking in the light when running. If it looks good my suspicions of a dropping cyl are wrong. If you are getting spark on all six, the shift switch is not the problem. To test anyway, all you do is unplug it and run.
I am really wondering about you saying ot was running fine, stopped, and then it was running bad. That sounds like electrical probs to me. Spark.

 

[daselbee]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Can you redescribe your symptoms? Now i am not sure exactly what is happening. From your first post, i got the impression that you could go to wot, but it would only top out at 3000. Now i get the feeling you are describing a severe bog when throttling up. Sorta confused now.

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

I'll pick up a timing light and see what I can find out. The oil is super rich because I run my kicker off the same tank and it also had some spent oil / gas coming out of the prop. I'm wondering if something with this new fly wheel is causing my problems.

Let me rephrase running "good" last season before I disconnected the VRO and still had the old fly wheel on it the motor would idle correctly and get about 5800-6k at WOT this years first time out after converting the pre mix new fly wheel etc it was idling pretty rough ( I contributed that to possible carb problems from sitting for a few months ) so all that said when I gave it the juice for the first time this year it would get 5k WOT also contributed that to carbs. But then yesterday it was running "ok" in the morning then in the afternoon it started doing all this mess so it could very well be a spark or timing issue with this new fly wheel. I've never messed with timing or checked timing on an outboard so this will be a learning experience.

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Yes I'm sorry my descriptions have been confusing. Let me tell you exactly what happend yesterday afternoon ( Note: Motor had been runing okay that morning for an hour at 4800 RPM but was rough and i could not get my normal WOT then after I got back to the house let it sit for an hour went to head back out and then the following happend) I idled down my canal at 1200 RPM it's about a 15 min ride. Then when I got to the channel I hit the gas and the boat would not plain the engine just got up to 3k ish RPM and thats not enough to get it out of the hole ( its a 21ft pursuit CC) so I came off throttle and it went to about 400 RPM stumbled and died , restarted on first crank smoked like hell so I tried it again same thing. Limped boat to the ramp got the trailer and went to power load the boat and engine did not have enough power to even get the boat up the trailer. It is like its severely bogged out or running on only a few cylinders.

 

[dehydrated]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Try running with the air box off dont run it long just a take off to see it it bogs or takes off. do you have the big bore carbs? does your air box have Baffles or is it just empty inside? Do you know what size your main jets are?

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Not sure what you mean by Baffles , the air box has a large foam gasket on it , and it has vents on the side ( Bad description I know ) but the model number of the engine is J225TXCUB if that helps. And I'm not sure if the carbs are large bore or not here is a pic maybe you can tell.

 

[dehydrated]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Cant tell from the picture theres a metal plate or sticker on the side plate on the carb on one of them up top.Your main jets behind the screw on the bottom of the carb bowl pull the screw and the the jet behind it then look for a number on the side if i had to guess i would say 62D.If your boat takes off with the airbox off i would say your running too rich.Remember dont run it long just a little test.

 

[Blake0912]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Okay I'll give it a try and get back to you on the number , I gotta work out of town this week so I can mess around with the boat till Friday. I'll hook up an auxiliary 5 Gal tank with a proper 50:1 when I do the test to see if that helps , also put in fresh plugs.
So if I understand this correctly having the air box off will allow more air to get to the carbs making it run more lean ?

 

[dehydrated]

Re: 87' 225 Johnson Rough Idle And Loss of Power

Having the air box off will lean it out . Just try a short burst out of the hole and then put the air box back.Sounds with the spark check that you might be getting too much fuel a timing light would help to know if its cutting out power wise but im thinking too much fuel might be your problem