Touchy Throttle

[MWBROWN]

1989 200 hp Black Max OC199873 21ft Renken.

The throttle is very touchy. When we push for more speed, there is very little
increase until we hit a certian point. Then the engine will take off and plane the boat. We can for from there to WOT at about 5200 RPM. When we throttle back, it is pretty much the same in reverse.

In the Gulf, we need more throttle control.

Is this throttle adjustment or carb adjustment or both?

Is Clymer the best repair manual for this engine.

Thanks in advance,

Mike

 

[gss036]

Re: Touchy Throttle

Do not waste your money on a Clymer book, buy a Mercury OEM manual.
Check your linkage hook up on the port side of the engine and see if it is sliding back and forth. The throttle cables do seem to stretch a bit over the years. My 89 200 hp Merc has some slop but not what you are describing. You do not want to just start loosening and tightening the linkage and levers as you can mess up the link and sync which requires special tools to get reset properly.
I have never messed with mine so can't help much there.

 

[j_martin]

Re: Touchy Throttle

Do not waste your money on a Clymer book, buy a Mercury OEM manual.
Check your linkage hook up on the port side of the engine and see if it is sliding back and forth. The throttle cables do seem to stretch a bit over the years. My 89 200 hp Merc has some slop but not what you are describing. You do not want to just start loosening and tightening the linkage and levers as you can mess up the link and sync which requires special tools to get reset properly.
I have never messed with mine so can't help much there.

Don't need special tools, unless a timing light is called special. The book calls for a dial indicator to check .462 BTDC measurement on the flywheel. You can just feel for top dead center with a bolt, and be sure it is at 0 on the flywheel. If you have a dial indicator or caliper (depth gauge), rig it up and use it.

Get the book, and go through the linkage and timing adjustments. This sort of problem is usually caused by tinkerers over a period of time.

Each engine has a specific sequence of idle timing, timing advance, throttle valve pickup and advance, and max timing. That's the link n sync adjustments you hear about. The adjustments aren't hard, but must be done in the proper sequence.

hope it helps
John

 

[MWBROWN]

Re: Touchy Throttle

Thanks for the replies.
I will get a OEM Manual.

Mike