507X5A 50 Hp Force idles very fast

[msstring]

This motor will idle fine. But usually it takes a long time for it to slow to a reasonable idle. Even when running in nuetral going fron fast idle to normal idle it takes a long time before it finally winds down. I have checked all the cable linkage and it seems to be ok. Wondering if the feul pump diagram could be leaking and takes a while to burn up the fuel buildup in the crankcase. Have you ever heard of that? Other suggestions?

 

[msstring]

Ruled out the fuel pump concept. Tried one off another motor and still the same. Have a new diaphragm on order anyway. Any suggestions on how to get this to slow down?

 

[msstring]

Here is a link to a video of it running. When you hear it start to run rough that is when I pull the throttle from fast idle to nuetral. It seems like it has too much fuel. Is there any adjustments to this carburetor? I need to get a book. But looking for some tribal knowledge on here. Somebody must have seen this ...

 

[jerryjerry05]

Does it do it in the water too?
Is there any pre-load on the throttle linkage?
​Sometime just a turn on the cable connector pulling the cable.

I see you have a spring loaded connector.
​Make sure there is a bit of tension when the connector gets put on.

 

[msstring]

Thanks Jerry, it did it in the water last year, hasn't been out yet this year. There is a fair amount of tension on the cable.

It will do the same even just opening the throttle directory on the carburetor.

There is a lot of gas and oil in my water barrel too.

 

[kbh121956]

There is a adjustment screw on the tower shaft, at idle it should be touching the block. When idling is the tower shaft moving?

 

[msstring]

The tower isn't moving at idle. I have adjusted that so I probably have it all messed up. I have been adjusting that and the rod that goes over to the carburetor.

 

[kbh121956]

msstring, I would pop off the rod that goes over to the carb at the tower shaft. Check and adjust the tower bolt so that it contacts the engine block while throttle is in neutral / idle position. If the carb linkage isn't off on adjustment, you should be able to snap it back on the tower without moving it. Please post results. Others will join in and give you advice. I'm wondering if the throttle cable hasn't slipped in the clamp?

 

[msstring]

I bought an on line manual (about time you say). Looked up how to adjust the idle mixture. It was set to 1 1/4 turns out. I set it to 1 per the manual and then adjusted it from there. Much improved! Idles down much sooner now, not nearly as much smoke or gas in my water barrel. I am anxious to put it in the water now. But still any additional comments, concerns or watch outs are welcome.

 

[msstring]

Thanks KBH, I will check that. Should it just touch or should the bolt hold it some amount? In other words, with the carb rod disconnected I turn the idle bolt out until it is free then back in until it touches?

 

[kbh121956]

On my 85hp, the tower bolt just touches the engine block. The linkage that operates the carbs when removed doesn't release (move) the carbs at all. Have you removed the bowl on the carb to see if any gunk is in it? Easy to with yours as you only have the one. Let us know what you find out. You are welcome, happy boating.

 

[msstring]

No Title

Finally got the boat in the water tonight. It ran great seems that the only issue was the idle mixture adjustment. Sometimes while trolling it would miss a beat or two. Not sure what that would be. I have 2 props a 293 12 1/2 and a 275 15. Can someone explain the difference?

 

[jerryjerry05]

The 12 1/2 and 15 is the pitch.
​That's the amount of forward travel in 1 rotation.
Google propeller pitch.

To decide what prop works best??
You'll need a tachometer.

​My twin 85's came with a 17P alum.
I wanted more power, speed.
I changed to a 19p

​I got 2-3 mph more speed and about 15-20% increase in fuel consumption.

​Since you don't have a tach(or do you??) you can try the different props and see what works best?

 

[msstring]

Thanks Jerry, I don't have a tach, was thinking about getting one just for fun. The 15 gives a couple more mph top end but the 12 1/2 is nicer for just trolling around with less load at lower rpm.