1992 150 johnson silver star

[hydrasports]

I have twin 1992 150 johnson (60 deg) outboards.The port engine wasnt reaching wot(4500) so i cleaned the jets with compressed air as advised on here but unfortunately that wasnt the problem.I then switched powerpacks from the starboard engine wich works fine to see if the powerpack mite be the problem.I took it out for a ride with the powerpacks switched and it seemed to reach 5ooo rpms but the other engine was reaching 5500 like always,so now I was confused.After fishing for a couple of hours the port engine (the one with the problem) starts up fine but dosnt want to go past 2800 rpms and dosnt seem to have power,it starts up right away idles with out shutting down but no rpms. can anyone help? also the powerpack thing has me confused when I switched it reached 5000 rpms but the other engine ran fine ? thanks

 

[hydrasports]

Re: 1992 150 johnson silver star

I should add,that the primer ball is firm and and I tried squeezing it to see if rpms would go, up to no avail.thanks

 

[clanton]

Re: 1992 150 johnson silver star

It sorta looks like it maay be stuck in S.L.O.W. which is set by the overheat sensor and holds rpms to app 2500 rpms.This could also be caused by powerpack,or power coil in stator. I would switch the power packs back and check ignition with timing light at full throttle, check each cylinder, light blink when engines misfires.

 

[hydrasports]

Re: 1992 150 johnson silver star

thank you very much clanton,I dont have a timing light so I will have to purchase one,if the power coil is bad would the engine still charge battery ? cause battery is charging when engine is running . thanks again

 

[clanton]

Re: 1992 150 johnson silver star

The power coil makes power for the logic in the power pack. If you can get to the tan wire on pack and unplug it, that should bypass S.L.O.W., then if it runs ok, you have alarm system problem.

 

[jegervais]

Re: 1992 150 johnson silver star

The power coil on this engine provides the operating voltage for QuickStart, S.L.O.W. and for the timing sensor. It really can't cause the engine to go into S.L.O.W. The design of the wiring harness (packard connectors)precludes disconnecting the tan wire at the pack, your only option is to disconnect the temp switches on each cylinder head. The port switch has 2 wires, tan (probably w/blu stripe) and white w/black stripe, the starboard connector has just the tan. If you disconnect the switches and your problem goes away, verify the engine's operating temp. BTW, does the alarm system function correctly?? If the engine is overheating, the hot-horn should be turning on. Have you checked compression and spark recently??<br /><br />-John

 

[hydrasports]

Re: 1992 150 johnson silver star

Thanks gentleman !! OK I disconnected temp switches from both heads,the engine now goes past 2500,I connected the temp switch wires back together and engine wouldnt go past 2500.The engine is running on garden hose flush and engine pees water strong,the temp guage on dash reads in the middle and I can touch heads and there not extremely hot so I dont think its overheating.As far as my warning horn,I dont think its working the other engine makes a beep when i first turn key this one dosnt and never has before.I ran the boat about 30 hours and never had a problem until yesterday.The other thing I noticed is now the engine idles at 1500 on garden hose and previously it would idle around 1000 on hose and when in water at 800. compression is between 98 -105 on all cylinders and all spark. thanks

 

[clanton]

Re: 1992 150 johnson silver star

I would repair the alarm system first.

 

[jegervais]

Re: 1992 150 johnson silver star

Are you getting in excess of 2500 rpm's running on the hose?? If you are running the engine above a fast idle (1500 rpm's) you need to be aware it can "run-away" (lack of back pressure). Run away can cause disasterous results, like a rod thru the block - take care not to "goose" the throttle when running on a flusher. I've seen engines that appear to run perfectly normal on the hose, but run like crap when the boat is in the water. <br /><br />I agree your alarm system needs repair - Also, if you didn't run the boat in the water, go back to the water and re-run it with the temp switch disconnected. <br /><br />-John

 

[hydrasports]

Re: 1992 150 johnson silver star

Thanks for all the help guys,john you make good sense,I wont run it high on house anymore.This thing needs to have the warning system working,plus whatever is causing s.l.o.w to kick in needs to be adressed,basicaly stuff for a professional like yourselves.Im going to make an appointment tommorow at the local johnson dealer and not run the motort until they fix it. All this help is greatly appreciated thanks.