Back to the same problem

[Gunner357]

I have an 1985 Mercury 150XR2 been threw all the stuff on the removal of the spark advance { do to my wires melted} that's the reason it got removed.... any way yes it is S&L'd many times and set to 23* WOT and 6* on idle the problem Im having is the idle rpm it seems way too high and I cant lower it the Boat runs great 65 MPH GPS but the Idle Boat tach is new and it says 1100 idle on a hose slightly less in the water I hooked my remote tach to it and it varies from 900 to 1200 clueless why it does that any anyone have any thoughts on this? thank you

 

[Sea Rider]

Welcome to Iboats,

Is it possible to adjust CCW the main idle screw, the one that controlls all carbs to leesen the idle rpm displayed ? 2 stroke motors have erratic rpm behaviour at idle specially with installed digital tachs, don't know about traditional dial/needle ones. When gearing forward from neutral, does the gear box engages with a dry clik like sound or a much louder clak one ? If with a clik the idle rpm is fine even if the tach says otherwise...

Happy Boating​

 

[Gunner357]

Welcome to Iboats,

Is it possible to adjust CCW the main idle screw, the one that controlls all carbs to leesen the idle rpm displayed ? 2 stroke motors have erratic rpm behaviour at idle specially with installed digital tachs, don't know about traditional dial/needle ones. When gearing forward from neutral, does the gear box engages with a dry clik like sound or a much louder clak one ? If with a clik the idle rpm is fine even if the tach says otherwise...

Happy Boating​

The Idle screw is off the stop so no
Engaging into gear sounds too loud too me compared to other boats it really seems to hit hard.
Today I Sync and Linked again re-timed
All is where all others are saying to time it in the forums W/O the stabilizer
I replaced everything on this engine even ALL engine gasket and put new Carson reeds in.....If I set the idle timing to lower it idles lower but stalls when in the water sorry forgot to mention that earlier.

 

[Sea Rider]

If in doubt, get a Service Manual for that motor and snych, link exact same per the factory Manual. With motor OFF and throttle backed up are all carb's butterflies remaining fully closed ? If not the idle rpm's will be much higher than should be, check.

Happy Boating​

 

[Chris1956]

Adjust your throttle cable barrell nut to push the throttle closed. That will lower the idle speed. I would recommend a 21* BTDC max spark advance, if you plan to use regular grade gasoline.

 

[Gunner357]

If in doubt, get a Service Manual for that motor and snych, link exact same per the factory Manual. With motor OFF and throttle backed up are all carb's butterflies remaining fully closed ? If not the idle rpm's will be much higher than should be, check.

Happy Boating​

Yes Verified butterflies today I do have a manual.....

 

[Gunner357]

Adjust your throttle cable barrell nut to push the throttle closed. That will lower the idle speed. I would recommend a 21* BTDC max spark advance, if you plan to use regular grade gasoline.

carbs are closed completely verified today

 

[Dukedog]

idle speed and/or rpm is controlled by tha idle timing ONLY (10/32 screw on tha timin' arm) no other screw should be turned ta adjust idle period... tha carbs have an idle circuit that can't be adjusted without changing tha jets.. tha numbers for idle timin' really have no bearing on what ya may end up with.. after all linkage adjustments have been done you you should have a very slight gap between tha carb roller and linkage cam.. tha line on tha cam should line up close ta tha center of tha roller.. idle timin' should be set with tha boat in tha water (on or off tha trailer) in gear ta whatever makes both you and tha motor happy.. if all this fails to get ya where ya wanna be you may need ta look at tha carbs....

as for as tha "barrel nut" adjustment goes ya make sure its what i call a kinda "pre-loaded" position.. in other words its tight enough to make sure it will have tha arm pushed completely against tha stop "anytime" control is pulled back ta idle and/or neutral.... and still have tha "slight gap" between tha roller and cam......

 

[Chris1956]

Carbs closed do not control the idle speed. Idle timing controls the idle speed. So back off on the idle screw and adjust the throttle cable to push the throttle closed (retarding idle timing) to control the idle speed.

 

[Faztbullet]

1100 RPM on hose is normal...no back pressure. Should see 900- 1000 RPM in water. As Duke said adjust to what makes motor happy not spec. I have had older motors like yours be happier at the 2-4 degrees than the 6 °. Make sure it has gap to help bogging

 

[Dukedog]

tha reason for disregarding tha "numbers" is this.. you are setting tha timing on ONE of six holes.. unless tha flywheel is indexed you have no way of knowing what it may or may not be on tha other five holes.. any one (or all five) of them may/may not be different from tha one ya usin' ta set timin'.. same applies ta MAX timin'.. its some kinda job ta try ta set max when runnin' at wfo thats why most set crankin' max a few degrees less than 25* Unless tha flywheel is indexed ....................

 

[Gunner357]

idle speed and/or rpm is controlled by tha idle timing ONLY (10/32 screw on tha timin' arm) no other screw should be turned ta adjust idle period... tha carbs have an idle circuit that can't be adjusted without changing tha jets.. tha numbers for idle timin' really have no bearing on what ya may end up with.. after all linkage adjustments have been done you you should have a very slight gap between tha carb roller and linkage cam.. tha line on tha cam should line up close ta tha center of tha roller.. idle timin' should be set with tha boat in tha water (on or off tha trailer) in gear ta whatever makes both you and tha motor happy.. if all this fails to get ya where ya wanna be you may need ta look at tha carbs....

as for as tha "barrel nut" adjustment goes ya make sure its what i call a kinda "pre-loaded" position.. in other words its tight enough to make sure it will have tha arm pushed completely against tha stop "anytime" control is pulled back ta idle and/or neutral.... and still have tha "slight gap" between tha roller and

idle speed and/or rpm is controlled by tha idle timing ONLY (10/32 screw on tha timin' arm) no other screw should be turned ta adjust idle period... tha carbs have an idle circuit that can't be adjusted without changing tha jets.. tha numbers for idle timin' really have no bearing on what ya may end up with.. after all linkage adjustments have been done you you should have a very slight gap between tha carb roller and linkage cam.. tha line on tha cam should line up close ta tha center of tha roller.. idle timin' should be set with tha boat in tha water (on or off tha trailer) in gear ta whatever makes both you and tha motor happy.. if all this fails to get ya where ya wanna be you may need ta look at tha carbs....

as for as tha "barrel nut" adjustment goes ya make sure its what i call a kinda "pre-loaded" position.. in other words its tight enough to make sure it will have tha arm pushed completely against tha stop "anytime" control is pulled back ta idle and/or neutral.... and still have tha "slight gap" between tha roller and cam......

I will go and verify the cam/roller now.... I know the Idle is set by timing and I did verify all carbs are closed...thx for the reply

 

[Gunner357]

Carbs closed do not control the idle speed. Idle timing controls the idle speed. So back off on the idle screw and adjust the throttle cable to push the throttle closed (retarding idle timing) to control the idle speed.

I know this the linkage is as far as it will go now.....thx for the reply

 

[Gunner357]

1100 RPM on hose is normal...no back pressure. Should see 900- 1000 RPM in water. As Duke said adjust to what makes motor happy not spec. I have had older motors like yours be happier at the 2-4 degrees than the 6 °. Make sure it has gap to help bogging

It idles around 1k in the water but hits hard when I engage that is what Im worried about... however mine is around 4* but was set at 6* cranking set.... someone told me to drop to 11* though??? not sure about that

 

[Gunner357]

tha reason for disregarding tha "numbers" is this.. you are setting tha timing on ONE of six holes.. unless tha flywheel is indexed you have no way of knowing what it may or may not be on tha other five holes.. any one (or all five) of them may/may not be different from tha one ya usin' ta set timin'.. same applies ta MAX timin'.. its some kinda job ta try ta set max when runnin' at wfo thats why most set crankin' max a few degrees less than 25* Unless tha flywheel is indexed ....................

Im not going by the service manual numbers just bt input from people that removed stabilyzer..... the flywheel is indexed do to issue earlier and was helped by CDI thx for the reply

 

[Faztbullet]

If you shifting too slow it will bang into gear, should be a smooth fast motion from N to F

 

[Chris1956]

ADI idle pickup timing should be between 0-9 * ATDC. It sounds like you should be closer to the 9* ATDC mark. That is after top dead center......

 

[Dukedog]

Im not going by the service manual numbers just bt input from people that removed stabilyzer..... the flywheel is indexed do to issue earlier and was helped by CDI thx for the reply

so tha flywheel has degree markings ALL tha way around it??? if so are you doing tha timing thing on tha cylinder that reads highest?

 

[Gunner357]

so tha flywheel has degree markings ALL tha way around it??? if so are you doing tha timing thing on tha cylinder that reads highest?

CDI had me mark around the flywheel when I was having issues when I changed switch boxes it was to check TDC on each cylinder and some other marks its been a while if that is what you was inquiring about its not marked from factory

 

[Gunner357]

ADI idle pickup timing should be between 0-9 * ATDC. It sounds like you should be closer to the 9* ATDC mark. That is after top dead center...... I re-timed last night its at 6* Im going to test it tonight.....