1989 GT 150 Idles Low at Lake High Home

[jamieogle]

HI,<br />I HAVE 1989 JOHNSON GT 150 IT IDLES LOW AT THE LAKE AND HIGH AT HOME. IT ALSO WILL NOT RUN AS FAST AS IT DID 2 OR 3 MONTHS AGO. I HAVE PUT NEW PLUG IN AND REBUILT CARBS. SOMEONE SAID TIMING MAYBE OFF. MY MANUAL SAY TO SET IT AT 28 DEG. AT 5000 RPMS. IS THIS CORRECT? THANKS FOR ANY HELP!

 

[wilde1j]

Re: 1989 GT 150 Idles Low at Lake High Home

At home, on muffs? Will always idle 200 to 400 RPM higher on muffs as opposed to in water. Timing doesn't changed, unless someone messed with it. Timing is whatever shop manual calls for. What is WOT RPM (now and earlier)?

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

Now WOT RPMs going down lake is 5000 to 5200 rpm max. 3 months ago 5600 rpm max.

 

[wilde1j]

Re: 1989 GT 150 Idles Low at Lake High Home

As I said, timing doesn't change by itself. All the plugs look the same? Possibly a coil is breaking down. You might buy one new coil and try swapping for the existing coils, one at a time and see if that helps the RPM loss. Do a search to find Joe Reeves' link and sync procedure, which allows setting the timing without running the motor. You'll need acess to a shop manual for the correct timing for your motor.

 

[emdsapmgr]

Re: 1989 GT 150 Idles Low at Lake High Home

WildeOne's advice is sound. You may be dropping a cylinder. Do a spark check.

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

Hi,<br />Timing was off,lock nut was loose. Thanks for all the help! <br /><br />Engine still has no top end speed. All I can get out of it is 4800-5000 rpms. I checked the compression and all were at 100psi give or take 5psi. I have new plugs and have rebuilt the carbs. I dont know what to do now.

 

[Dhadley]

Re: 1989 GT 150 Idles Low at Lake High Home

What did you set the timing at?

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

I set it at 24 deg per Joe Reeves no running. Which should be 28 deg ( 28 deg per tag on engine ) when enigine is running. Also what should the compression be if it new or just rebuilt.

 

[emdsapmgr]

Re: 1989 GT 150 Idles Low at Lake High Home

Your compression readings are just fine. Time to do some ignition system tests.

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

Like what, buy one new coil and try swapping for the existing coil?

 

[tashasdaddy]

Re: 1989 GT 150 Idles Low at Lake High Home

when you rebuilt your carbs did you do a 'link n sinc'.

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

I am not sure if I know what you talking about. Is that where you loosen the linkage and make sure all carbs. are closed?

 

[emdsapmgr]

Re: 1989 GT 150 Idles Low at Lake High Home

Run the engine on a garden hose. Put a timing light on each wire and check for strong, constant flashes from each.

 

[jamieogle]

Re: 1989 GT 150 Idles Low at Lake High Home

Checked yesterday, all look the same to me, Strong flash on each.<br /><br />I do remember when I rebuilt the carbs. that the floats were not parallel before the rebuild. And when I set them Parallel with the gasket as my manual said they should be set, the carbs. leaked fuel.<br /><br />I also wanted to know if the seloc manual is a good one or do I need a different one?