48 hp spl bogging

[Paul deBoer]

Hello all,<br />I have a 1996 48 hp spl johnson that's giving me a little trouble. Sometimes, when trying to punch it out of the hole it bogs and will only run at an almost low idle speed (approx 8 mph). Shutting it off and restarting does nothing either. Other times it gives me no problems whatsoever. Squeezing the primer bulb did nothing at all and I suspect that I am drawing air in from somewhere. The problem seems to come and go whenever the gas tank is taken out for refueling. It's a brand new tank also. How do I check the anti siphon valve? I just replaced the fuel line and bulb assembly and the new bulb will not pump up either. I can hear air pumping back into the tank when the bulb is squeezed, and yes it is hooked up correctly. How does one go about finding an air leak? Also what are the chances that my newly purchased fuel hose assembly is not working? I'm new to this boating game, and I never thought I'd say this but....I'm already tired of playing with my johnson!

 

[rickdb1boat]

Re: 48 hp spl bogging

My thoughts are leaning toward an intermittant sticking float in the carb or a bad connection at the fuel tank or motor allowing air to "Sometimes" enter the system. Did you replace the fuel line assembly with an OMC one or the Tempo type? If the latter, there is a good chance that it's bad. They are known for poor primer bulbs and connectors. Also, I assume you are running a portable tank? Did it do this before you installed the tank? You may have a weak fuel pump diaphram(Cheap on those motors). You just replace the whole pump. If you hit the choke for a second or two when it boggs, what happens? Since you are new to the boating scene, I assume you have not had much experience with outboards? A Manual is invaluble for troubleshooting these type of problems. I would get a Factory Manual at the link below. Can you give anymore history on the engine that may help us? Is this a tiller model or remote? Are you using fresh 87 octane fuel? 50:1 mix? Is the idle speed correct(High enough in gear)? Those are great motors, by the way.. We just need to weed out the problem.<br /><br /> Factory Manual

 

[Paul deBoer]

Re: 48 hp spl bogging

The fuel line was a Tempo model, and yes it is a portable tank. The problem did exist before the new tank as well. How difficult is it to replace the fuel pump? I didn't try the choke when it was bogging....didn't even think about it. I do have limited experience with outboards but am fairly mechanically inclined, so I'll pick up a manual on Monday. I'm stuck on night shift here this weekend. It is a remote model and I know it sat for the better part of last year before I bought it. Problem has occured with fresh fuel (87 octane) idle speed the motor purrs like a kitten and mix is 50:1. Hope this info helps a little more. I plan on getting some new plugs as well. I know I should have changed them first but the fish were calling. If I can find a fuel pump in my travels I just might pick up one of those as well. Any more help would be greatly appreciated. Thanks.

 

[rickdb1boat]

Re: 48 hp spl bogging

deBoat <br /><br />A change of mind with the new information you gave. Lets forget the fuel pump for now. Try the new spark plugs first and see what happens. If that does not help and If it sat for a long time, odds are your low speed jets and/or your float needles are sticking and causing the problem. This will require removing the Carb(s), cleaning them with carb cleaner, compressed air to blow threw the passages and using a rebuild kit to fix the problem. When a motor sits that long, the carb jets, float needle seats and so forth gum up with stale old fuel and can not function properly. This is where you need to start if the plugs don't help. Also, make sure your Sync and lync are correct before getting into the carbs. The Manual will get into that. Basically just means that your throttle plate(s) are opening at the same time in conjunction with the timing. Parts are readily available at your dealer or online. Carb is Not a bad job if you have the Manual and take your time... Lets hope you can get by without it. Start with the basics. Spark Plugs, Lync and sync...

 

[Paul deBoer]

Re: 48 hp spl bogging

Thanks Rick,<br />I'll give it a whirl and let you know what happens. I won't be able to get the stuff until Monday. As far as the bulb goes I think I'll take that back too. I'll look for an OMC one this time.<br />Paul

 

[Paul deBoer]

Re: 48 hp spl bogging

Well, I finally got a chance to get out and try the boat again this last weekend. I asked my wife to pick up some new plugs for me some time ago. I couldn't quite figure out why the champion numbers didn't quite match the NGK plugs that I had taken out. After a little research it appears that the previous owner had been running the wrong plug. Now, after putting the correct plug in the ol' girl runs like a scared rabbit. The only question I have is......could running the wrong plug have done any damage? It was only used once like that.<br />Thanks,<br />Paul