15 Hp Johnson four stroke

[cdupuis]

Gents..... Having a problem with my 1998 15hp Evinrude 4 stroke Outboard... It will start and idle like a champ in gear and out of gear in the lane way with the muffs on, I can rev it no problem.. As soon as I put the boat in the water and give it gas, it sputters and dies and wont start again.

Mechanic recommended a new electronic part but it costs $469. which is fine if it fixes the problem but I want to hear what others have to say.

Part recommended is OMC586136 located under the flywheel.

 

[TLL]

Re: 15 Hp Johnson four stroke

Sure sounds like a lack of fuel problem to me. A dirty carburetor will give these exact symptoms. In the driveway there is no load on the engine and fuel needs are small. As soon as you put the boat in the water and accelerate, the fuel needs are greater than the carburetors ability to supply it. The motor dies and is very difficult to try and restart. This is where I would start.

 

[boobie]

Re: 15 Hp Johnson four stroke

Check your compression to see if that's okay. Then get an open air gap spark tester and set it to 3/8". When the mtr quits, check the spark. If no spark your mechanic was right. If spark, look for other probs.

 

[cdupuis]

Re: 15 Hp Johnson four stroke

Check your compression to see if that's okay. Then get an open air gap spark tester and set it to 3/8". When the mtr quits, check the spark. If no spark your mechanic was right. If spark, look for other probs.

Compression is 105 in both cylinders. Boat is in storage for the winter will try the gap spark tester in the spring..

Thanks for your help..

 

[cdupuis]

Re: 15 Hp Johnson four stroke

Sure sounds like a lack of fuel problem to me. A dirty carburetor will give these exact symptoms. In the driveway there is no load on the engine and fuel needs are small. As soon as you put the boat in the water and accelerate, the fuel needs are greater than the carburetors ability to supply it. The motor dies and is very difficult to try and restart. This is where I would start.

Boat is in storage for the winter will have mechanic check carburetor in the spring..

Thanks for your help..

 

[dkonrai]

Re: 15 Hp Johnson four stroke

could be your fuel pump too. i had the dame issues on the same motor. it ended up being a torn diaphram on the fuel pump.

 

[cdupuis]

Re: 15 Hp Johnson four stroke

So are you saying that yours ran fine with the muffs on out of water but quit when you put it in water?

 

[cdupuis]

Re: 15 Hp Johnson four stroke

Thanks, for the input, will get mechanic to check carb and replace fuel pump in spring. Very frustrating having it run so well in the lane way then put it in the water and have to use my trolling motor to get it back on the trailer...

 

[boobie]

Re: 15 Hp Johnson four stroke

I'm still sticking with my post until the spark is checked.

 

[dkonrai]

Re: 15 Hp Johnson four stroke

I'm still sticking with my post until the spark is checked.

yes i agree +1. spark, compression, fuel. thats pretty much it. when i had issues with my motor, it would fire up, run, then die. it had 130/130, and i had spark. problem was i was making oil and the motor kept dying. i had fuel starvation, not to say you do too. listen to boobie, and check that compression (your just looking for even pressure), and spark. fyi, cleaning the carb and checking the fuel pump is pretty easy.

dino

 

[the machinist]

Re: 15 Hp Johnson four stroke

Don't forget the posibility of it only firing on one cylinder. These motors run quite well with no load on one cylinder.

 

[cdupuis]

Re: 15 Hp Johnson four stroke

Don't forget the posibility of it only firing on one cylinder. These motors run quite well with no load on one cylinder.

Mechanic said there were two different plugs in the motor so he replaced both with new plugs. Could this have been the cause of the problem?

 

[boobie]

Re: 15 Hp Johnson four stroke

Did you run it after he replaced the plugs ??

 

[cdupuis]

Re: 15 Hp Johnson four stroke

No I didn't run it as the mechanic winterized the motor. -25 here today with the windchill so will do it in the spring and test it under load while the boat is on the trailer. Have to get one of those spark plug testers. Thanks for your help..

 

[boobie]

Re: 15 Hp Johnson four stroke

Sorry to hear about your -25. It was only 84* here today. I'm from northern WI so I know what cold is. Burrrrr.

 

[Xsteweyx]

Hi sorry new to this but just to say that I have the same engine which dies as soon as I throttle it past half way and was told to get a new cdi unit which I did at a very expensive price and of course it Did nothing I managed to get some money back but be carefully and get the cdi unit checked before changing it

 

[racerone]

Inspect valve rocker arms.

 

[GA_Boater]

Old thread and Xsteweyx has started a thread of his own.

Closed.