Johnson oceanpro 150 missfiring

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Johnson Oceanrunner running poorly:

No answers to date:

Engine seems to skip a beat at 3,800 ? 4,000 RPMS sometimes a lot higher and sometimes not at all, but most of the time it will miss. When I pull back it immediately goes away

Already replaced

Eye sensor
Coils
Wires
Plugs
Pack
Gas filters
Gas

Had professional look at it swore it was the pack and/or eye. Not that.
Any ideas besides keep using it until it really brakes?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Johnson oceanpro 150 missfiring

What spark plugs are you running? What fuel?
 

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Re: Johnson oceanpro 150 missfiring

The spark Plug I'm using is a Champion QL78YC gapped at .30

Gas always used 87. I put some 89 in when the tank got a little low, but didn't see a difference.

Motor is a 1996 150 60deg Problem started right from day one this year after winter storage. Never a problem before.


Thanks for your assistance
 

grid

Petty Officer 1st Class
Joined
Oct 29, 2002
Messages
232
Re: Johnson oceanpro 150 missfiring

Your last post leads me to believe there's a piece of winter-scum floating around in one of the carb bowls. Electronics generally occur seriously all at once, or ease into things, not just happening erratically immediately after storage, at upper RPMs.
 

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Re: Johnson oceanpro 150 missfiring

Thanks for the help Please read on:


I had thought that may be it as well, but why so prevalent at 3,800 RPMs where it happens 80% + of the time?


Also, what really bothers me is it seems like the whole engine is shutting down, because at higher RPMs +4100 the engine seems to Bang at the lower unit as if I?m restarting in gear. It?s like its shutting off then restart very fast.

Also (not sure) but won?t these engines run on less than one or even two cylinders without any hiccups?
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,320
Re: Johnson oceanpro 150 missfiring

what year is the motor... is it carbed or ficht?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Johnson oceanpro 150 missfiring

You're positive that you are not overheating at all? Have you checked spark to start? BTW Jason it is a 96
 

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Re: Johnson oceanpro 150 missfiring

First the engine is carb.

I'm not overheating because it started right away in the spring shortly after leaving the dock with water temps in the low 60s and I have the system that checks for that stuff in the tac.

However, I did overheat the prior year a number of times and replaced the waterpump and thermostats prior to this year. I was thinking maybe there's a sensor thats not right, but it's not the same miss as when the system shuts you down for an overheat. the miss is almost rythmic if I let it continue to miss, but I usually slow down a bit and it goes away.

It also seems to be load related the more weight or wind it happens earlier.


What is the spark to start check?

Keep in mind I did have an OMC expert out and he did timing light stuff pulling wire ect while I was running and missfiring.
 

hangman1176

Recruit
Joined
Dec 11, 2007
Messages
5
Re: Johnson oceanpro 150 missfiring

I'm going with a fuel/water seperator needs replacement. Take it off and turn it upside down. If not still going with a fuel problem at the engine or tank. Good luck.
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,320
Re: Johnson oceanpro 150 missfiring

sounds like you have a carb leaning out.
 

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Re: Johnson oceanpro 150 missfiring

Capt J

What do you mean by leaning out??

How would you test or fix for that?
 

kmdfluker

Seaman Apprentice
Joined
May 29, 2007
Messages
33
Re: Johnson oceanpro 150 missfiring

Anyone else with any ideas -

Please explain this lean thing and what to check for.
 
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