Help

[lyncraft_mechanic]

As you may know I have 2 other postings in regards to the same old problem and seem to be getting lost among all the new threads!!!! Here is my problem and what i have already ruled out. its a 2002 40hp johnson that is only obtaining 3000rpm at WOT with a top speed of 25mph (by GPS and speedometer) on a 14' boat. I just changed the sparks plugs and they are burning properly, the system check is working and displays no warnings of any kind. the engine is definetly not overheating and it is not in S.L.O.W mode, no problems with the throttle linkage and finally there is no sign of fuel problems since the primer bulb stays hard and the engine runs strong!!!!!!!!!!!!!!!!!!!! Any other ideas or suggestions??????

 

[reload]

Re: Help

The primer bulb is only to get the gas to the motor and prime the pump. Once you are running the pump pulls fuel from the tank by suction. You say you can only get 3000 r's out of it, then you say it is running strong. This leads me to believe you have throttle problem or the carbs are clogged. I would start by checking the compression and spark to rule those out.

 

[lyncraft_mechanic]

Re: Help

Thank you for such a quick response I will rebuild the carbs monday and recheck the spark!!!

 

[da_ardvark]

Re: Help

Just a little suggestion. Instead of posting another thread, simply go to your original thread and type a message simple of "bump". This will take your thread back to the forefront and will also allow all of us to read all of the information regarding your problem. It's a good way to keep all the info in a single spot.


Denny

 

[chbailey]

Re: Help

Be sure to get the spark and compression check done first. Carbs kits are good to have on hand but always do these tests first before you move on. Past that, I'm guessing carbs.

 

[lyncraft_mechanic]

Re: Help

Today i tested the compression and have 124 psi on both cylinders, the spark also tested strong. do you think i should rebuild the carbs?

 

[lyncraft_mechanic]

Re: Help

"bump"

 

[HighTrim]

Re: Help

Is this boat new to you?? When did it change?? Any change to the set up? By that i mean the motor height, prop, etc... I think if you had a carb issue you would know it, but you say the motor runs strong.

 

[lyncraft_mechanic]

Re: Help

The boat is not new to me but the motor is. my setup has changed a little bit with the addition of a jack plate but how does this affect the rpm's of the motor??? I know it is not the prop since i have a spare. I am going to rebuild the carbs in the morning any other suggestions????

 

[Dizz]

Re: Help

Just curious,and I`m sure not one of the experts around here,but I`m wondering if both your props are the same pitch?Would it be wotth the effort to try a lower pitch prop to see if that brings RPM`s up?The pitch should be stamped on the prop.That`s a small boat for that motor,but is it possible someone has changed props for a very light boat?Just a thought.

 

[lyncraft_mechanic]

Re: Help

I have two different pitch props which are 11 3/4x17 and 12 1/4x15 that i have tried so far with no change in my RPM's. the motor acts like it is stuck in S.L.O.W mode because I am in the range of 2800 to 3000 rpm @ WOT, but have never had any sort of alarms that would suggest this!!!!! any suggestions would be helpful . thank you all for your help so far

 

[lyncraft_mechanic]

Re: Help

bump