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2007 BF 50 won't return to idle

J

Jamie McCormick

New member
Intermittently after motoring ,when I pull back on throttle. 2007 Bf 50 it will only rev back to about 2000 rpm,I then have to wait 1,2,5, minutes and then it will drop the rest of the way back to idle before I can shift to neutral Obviously very annoying and dangerous when wanting to slow down and go to neutral. Or it also happens when starting, intermittantly having to wait a longtime for rpm to return to idle before it can be shifted into gear.....any help would be much appreciated
 
The solution will be different depending on if the engine is carbureted or fuel injected.

I'm going to guess fuel injected and go down that path.

If your engine is FI, then you will have a THROTTLE BODY (TB) that is used to control air entering the intake and this will directly control engine speed as a result. Here's a link to a parts page for the throttle body assembly:

http://www.boats.net/parts/search/H...d Later/BF50DK2 XRTA/THROTTLE BODY/parts.html

You may notice that there is a section of linkage that attaches to a swivel on an arm on the throttle body. That is where the motion of your throttle control lever and cable terminates.

The arm controls a "throttle plate" or door, if you will, that allows air to enter the engine. At the same time the plate is moved, a sensor that is bolted to the throttle body....called the throttle position sensor (TPS)...is also being moved to signal the engine computer what that throttle plate is doing. IE: closed....wide open....or anywhere in between the two.

The first thing I would check for a complaint such as yours would be that the plate is being moved and then fully closes each time the throttle control is moved. They are known to sometimes "hang up" or be "sticky". Also, that small section of linkage in the parts diagram can bind and not completely transmit the movement of the cable to the TB.

What I have just described is the MECHANICAL function of the throttle control for your outboard (if it is a fuel injected engine). It would be somewhat similar if the engine were carbureted in that there are linkages and throttle plates to check for proper operation.

With a fuel injected engine though, there is also the ELECTRONIC side of engine speed control. So....if a check of the throttle body operation doesn't reveal any faults....there could be other reasons the engine balks at returning to idle.

If that's the case....get back to us with your findings and we will try another approach.

Good luck.
 
Last edited:
jgmo said:
The solution will be different depending on if the engine is carbureted or fuel injected.

I'm going to guess fuel injected and go down that path.

If your engine is FI, then you will have a THROTTLE BODY (TB) that is used to control air entering the intake and this will directly control engine speed as a result. Here's a link to a parts page for the throttle body assembly:

http://www.boats.net/parts/search/H...d Later/BF50DK2 XRTA/THROTTLE BODY/parts.html

You may notice that there is a section of linkage that attaches to a swivel on an arm on the throttle body. That is where the motion of your throttle control lever and cable terminates.

The arm controls a "throttle plate" or door, if you will, that allows air to enter the engine. At the same time the plate is moved, a sensor that is bolted to the throttle body....called the throttle position sensor (TPS)...is also being moved to signal the engine computer what that throttle plate is doing. IE: closed....wide open....or anywhere in between the two.

The first thing I would check for a complaint such as yours would be that the plate is being moved and then fully closes each time the throttle control is moved. They are known to sometimes "hang up" or be "sticky". Also, that small section of linkage in the parts diagram can bind and not completely transmit the movement of the cable to the TB.

What I have just described is the MECHANICAL function of the throttle control for your outboard (if it is a fuel injected engine). It would be somewhat similar if the engine were carbureted in that there are linkages and throttle plates to check for proper operation.

With a fuel injected engine though, there is also the ELECTRONIC side of engine speed control. So....if a check of the throttle body operation doesn't reveal any faults....there could be other reasons the engine balks at returning to idle.

If that's the case....get back to us with your findings and we will try another approach.

Good luck.
Click to expand...
thanks for the prompt thorough response ,,The motor is actually carborated,wished I had of known to mention that,not sure if that makes the issue simpler or not,linkages all seem to be clean and have grease on them ,must be the "plate"you refer to,will see if there is something there I can stumble on,thanks again for taking the time to post a reply ,Jamie
 
Yes...it would have saved me a lot of typing had you listed carburetor.

Anyway....I'm sending the parts page link below for you to inspect. It is labeled "Throttle Rod". My GUESS is that your problem could likely lie with one, or more, of the parts on this page.

First there is the throttle "cam" (item #15). It can wear or get bent and not allow the linkage to work smoothly. That cam and the other parts related to it can cause the throttle to stick.

For instance; if the attaching flange bolt (item#18) has worked loose, the whole affair could hang down and not work smoothly. Or, the opener cam return spring could be weak or broken. There is the item called "collar" (item#21) that rides in the big, arced slot in the cam plate. It must move smoothly throughout the slot and not have any flat spots worn into it. At full throttle, it is supposed to be adjusted to sit at the top of the slot where the arc takes a 90 degree bend and forms a sort of "perch" for it to sit on. It is the first piece of the "puzzle" that transfers the movement of the cam to the throttle arm of your lower carburetor.

One of the USUAL SUSPECTS for a hanging throttle is the anti-stall dashpot assembly (item #5). It is there to keep the throttle from "slamming shut" and stalling the engine when the throttle is pulled back too fast. But if it gets sticky, it can cause your symptom.

Look all of that over carefully. If you take the throttle rod (item #10) off of the cam swivel, you can operate everything by hand and get an idea if there is any roughness there.

http://www.boats.net/parts/search/H...nd Later/BF50AK0 SRJA/THROTTLE ROD/parts.html

Also, note that there is the letter/number combination E-14 in bold type with a pointing arrow near the dashpot assembly. That indicates an associated part on another page......page 14 of course. I posted the link to that page below.

http://www.boats.net/parts/search/H...Later/BF50AK0 SRJA/CARBURETOR ASSY/parts.html

Page 14 lists item #18....check valve, dashpot. It is tucked in just behind the dashpot control rod. That valve controls the rate at which the dashpot assembly "cushions" the throttle's return to idle. It has an "orifice" in it to slow down the rate of vacuum bleed from the dashpot diaphragm. But...it SHOULD allow SOME movement of the rod during de-acceleration. If that check valve gets any dirt or debris inside.....well.... it MIGHT hang up and THAT would hang up the dashpot and THAT would cause your throttle to hang.

If you place the end of the check valve that is connected to the dashpot through the vacuum line to your lips and suck on it like a straw....it should prevent full, free movement of air but NOT be completely blocked. If the valve is blocked you may want to replace it or try cleaning it out with a mild solvent like WD 40.

Good luck and let us know how you make out.
 
Deanmck said:
How did you go Jamie? Is it fixed? I'm just wondering for future reference.

Cheers
Dean
Click to expand...
Thanks for your help turns out problem was with the the collar hitting the sides of the slot in the cam , which restricted a Smooth return back to idle. My mechanic was telling me the caller should not touch the sides of that cam arc ,all the fix required was loosening of the cam screw realigning and tightening back up ,simple🙂
 
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