weak reverse throttle

kentam
Posts: 7
Joined: 21 Jul 2014, 23:03
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weak reverse throttle

Post by kentam »

I have a 90 HP outboard that has a weak throttle response when the control box is shifted into reverse. The forward has full throttle response. I bought the boat used and have lived with it up to this point, but would like to correct this issue. I have taken the cover off the motor and shifted it from forward to reverse and can see the cam that opens the throttle linkage (at the engine). In forward it opens all the way, but in reverse it is barely moving ( when engine running and in reverse, it is barely over an idle). My question is, should I be adjusting the linkage at the motor or is there adjustments for the cable inside the control box? I do not see anything on the control box to identify its brand. Thanks for any advise.

kentam
Posts: 7
Joined: 21 Jul 2014, 23:03
6

weak reverse throttle

Post by kentam »

The other thing I forgot to mention is that the warm-up lever also has no throttle response.

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JL8Jeff
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Joined: 26 Oct 2013, 14:56
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Location: Ewing, NJ

weak reverse throttle

Post by JL8Jeff »

Sounds like the throttle cable needs to be adjusted. I don't have my boat here right now so I can't look at it to say for sure but it sounds like it needs adjustment at the motor. Reverse has a limited range of throttle as does the start up lever. Forward has a large range so it might feel ok but there could be slack before it really starts giving throttle. You should be able to take the motor cover off and try moving the start up lever to see if the throttle even moves.
2001 Lowe Roughneck 1652 VT with Merc 60/45 jet 2 stroke

kentam
Posts: 7
Joined: 21 Jul 2014, 23:03
6

weak reverse throttle

Post by kentam »

Thanks for the info, that is my thoughts too. Just don't know if I adjust it to improve the reverse, will it change the forward in a negative way

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JL8Jeff
Posts: 802
Joined: 26 Oct 2013, 14:56
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Location: Ewing, NJ

weak reverse throttle

Post by JL8Jeff »

It sounds like there is too much slack so if you can tighten that up, it should help the reverse, the start up lever and even forward should come in sooner. If you go too far, when you shift to forward, it might rev too high for a low idle so you would need to back it off at that point.
2001 Lowe Roughneck 1652 VT with Merc 60/45 jet 2 stroke

turbotodd
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Joined: 24 Dec 2011, 22:06
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Location: 72032

weak reverse throttle

Post by turbotodd »

sometimes you can adjust the linkage and that'll take care of it. Other times not. Don't know what 90hp motor you have but some of the 60/40 Yamaha Jets (F40JEHA) have a different mapping for the EFI (and ignition timing) based on gear position. This is done because the jet loads the engine differently. Perhaps yours is similar but it still should throttle up in reverse, if only just a little. Power in reverse is normally reduced via linkage "stops", but should still be able to get about 1/4 throttle.