johnson 1995 40 hp throttle setting and timing

[scrapper042000]

hi ,I have a 1995 Johnson 40 hp I set the throttle cam according to the book but it could idle better ......rebuilt carbs ,eliminated vro ,added new fuel pump mounted it to vacuum port similar to older 50 hp ,no fuel leaks also starts hard warmed up after it sits a few minutes ......

 

[SparkieBoat]

a lot of older 2 strokes start hard when hot/warm. I like to give mine just a little throttle and start it in gear (you have to bypass the neutral safety switch). or you could just pull your idle lever up some, should start right up then. advance your idle timing just slightly to give a little higher rpm idle. maybe your carbs need cleaning in the idle passages. you c
should check your compression and make sure thats not an issue

 

[scrapper042000]

carbs I did this morning with omc kits cleaned all passages ,comp 140 on both cylinders .....backed in the water and it responds very well plenty of power strong and steady .....I did check the idle timing according to the book set it to about 3.5 to 4 at idle book said 2 degrees ...wot is 19 but im not concerned about wot yet.....I did set the throttle cam and front and rear ,but had to turn the idle screw up a ways ,I don't really care for the plastic throttle cams on this one after the intial settings I wasn't impressed .....set the carb linkage with plates closed so the roller was even with the arrow and set the rear throttle cam as well ....

 

[scrapper042000]

it doesn't spit or kick back at all ,so I believe I have the carb throttle plates synced in fairly well .....this motor is not responding very well to any adjustments on the linkage ..even starting over with the throttle cable removed

 

[SparkieBoat]

I am not sure exactly what you have going on there. I thought you were just having trouble starting a warm/hot engine. what symptoms are you having?

 

[scrapper042000]

using the worthless seloc manual I have doesn't seem to do the trick ....when its warmed up it will slowly start to slow down and die after about 15 seconds ,starts good cold and runs fine .....the link and sync method in the seloc manual really didn't respond well with this motor ,I did set the timing as well .I think I need to take a second look at my throttle linkage ,ive never had one respond as peculiar as this one ....im wondering if the throttle plates are too far open during start when warm it acts lean at that time trying to start ......lean and or spark advance rod in the wrong position due to linkage not responding correctly ...

 

[scrapper042000]

the front roller off the carbs was easy to align to the arrow on the front cam ...the big throttle lever (cam )farther back also has an arrow to align ,but it seemed difficult to align the marks even with the idle stopped backed off .

 

[SparkieBoat]

well you definitely need to get the linkage adjusted properly. but as far as the hot/warm starting problem, try pumping your bulb first and see if that helps. fuel can evaporate from a hot carb bowl pretty fast sometimes. also make sure your float is set properly in your carb. i am leaning more towards the carb itself than the linkage. but since you messed with it you now probably need to get it right again. what is the history of this motor? did it run fine before and suddenly start this problem?

 

[scrapper042000]

this motor came from a friend ,what I did find was the bushing back on the throttle cam/plate was gone ,im thinking I wasn't getting the right amount of timing advance ,now it seems to working good idles and shoots right out of the hole ,no hesitation .....motor does seem to have low hours and good comp 140 psi each cylinder ....

 

[SparkieBoat]

140 is great compression. get your timing set right and your linkage right and carbs clean and fuel flowing properly and that motor should run out strong. you may want to run 93 octane in that motor. I would not say that you have too but you would see a performance gain as well as MPG increase. It may help you motor to last longer as well.