Not Getting Full Power From Engine

[jsmendzi]

I have a 2004 40hp Johnson outboard model # J40RSRS that I purchased used about a month ago. After having to replace the flywheel (sheared key ripped the inside apart) I have gotten it to run pretty good. However, it has been difficult to get it to idle properly. When I received the motor, the idle screws were at about 4 turns out, and after spending much time adjusting them I find that it idles best at 4 1/8th turns (seems like a lot to me), however it doesn't seem to be a smooth idle. It sounds fine, then it hiccups like it is about to die every five seconds or so, then continues to idle fine for 5 seconds, and hiccups again. When running at WOT sometimes the revs move up and down like you were turning the throttle back and forth, to go faster then slower. Does anyone know what may cause this, and at how many turns the idle screws should be set at by default??? I have put a new carb kit on the carbs, cleaned and blow out the idle holes, cleaned the fuel filter, checked the fuel lines etc. It almost seems like it is not getting enough gas, so it starts to slow down, then as soon as it starts to slow down it has enough gas to speed up again. Any help would be greatly appreciated. Thanks.

 

[Solittle]

Re: Not Getting Full Power From Engine

I'd start by rebuilding the carb. - - get the crud out - - then do the adjusting.

 

[Goodoleboy]

Re: Not Getting Full Power From Engine

RPMS moveing up and down....also called surgeing.<br /><br />Is nearly always caused by faulty fuel pump.<br /><br />Note I said nearly always. A sticking float can act just like it.<br /><br />If your danged shore the float aint cocked side wise and rubbin against the bowl...and then droppin down..and then rubbin back up again.<br /><br />Then take a good look at the fuel pump.<br /><br />And just like solittle said...could be crud yet in the carbs.<br /><br />Gota pull em pesky little welch plugs out in order to get at the crud thats hiden underem.<br /><br />And take a sharp probe and see if the lead shot plugs are still tite..if they come lose..it will suck air around them...Wont idel worth 2 cents...and can cause lean fuel mix....big time troubles then.....like BANG.<br /><br />Good news is...they almost never come lose!<br /><br />Luck tu ya!

 

[jsmendzi]

Re: Not Getting Full Power From Engine

Thanks for the info. I have already cleaned the carbs twice, they are absolutely spotless... the motor has only been used for 15 hours at most. It doesn't appear that the floats are sticking, I have tried using different floats to be sure. If I disconnect the fuel line, how much fuel should be coming out of the end of it when turing the motor over?

 

[Goodoleboy]

Re: Not Getting Full Power From Engine

I supose you are talking about disconecting the line from fuel pump to carbs.<br /><br />As you crank the motor over, It should spurt a good stream thats in time with the motor revlutions.<br /><br /> If the motor were running on its own power it would be so fast as to look like a constant stream.<br /><br />If their are places where it stops for a couple seconds and then starts again for couple seconds.<br /><br />Then I would call it faulty.<br /><br />Good luck!

 

[L B Fisherman]

Re: Not Getting Full Power From Engine

i have always heard that 1 and a half turns on the idle adjust was where u wanted to start!

 

[jsmendzi]

Re: Not Getting Full Power From Engine

Would a fuel pump on a 1yr old motor with only 15hrs on it go? There is a good amount of fuel coming out of the line to the carbs... is there any way to tell whether the motor is getting enough gas?