1989 johnson gt 150

[madawaskabass]

Hi Rusty

After reading a bunch of your posts about decarbing I did it to my johnson 150 this weekend for the first time. I must admit that I couldn't believe the amount of stuff that seemed to come out in the exhaust. Motor sure does seem to start easier and run smoother now although maybe it's just in my head. I still am trying to track down my tach problem and had a try at it this morning. I checked the charging voltage at the battery with the motor at idle and it was just under 13volts but as soon as I increased the idle it would jump to over 16. Is this an indicator that the voltage regulators are bad? Are they the 2 little black squares that are located in the black box thats directly in the center on the back of the motor? I removed these and tried to test them for resistance and the only way I could get them to test showed 77 olms on each one. Any help would be great. Thanks for all the good info already and this board is simply a must read area for anyone with an omc.

[RUSTY63]

The regulator/rectifier is the box bolted on top, rear, about half of it is under the flywheel and it sounds like its bad.

Those small black boxes are the trim relays.

Thanks for the kind words and Glad we can help.

[madawaskabass]

Never mention the kind words. Thanks for the help, its all truely appreciated. I think I'll let my mechanic have a look at it as it may be a little out of my league.

[RUSTY63]

If you feel its more than you want to tackle then have your dealer check it out.

[ChampioNman]

You can do it but the Flywheel has to come off to get to it and you'll need a flywheel puller for that and a 1 1/4" wrench for the flywheel nut. CM

[madawaskabass]

Thanks for the vote of confidence. I think I have the puller so I may decide to give it a shot. Am I correct in thinking that the rectifier and voltage regulator are one unit or can you simply just replace the voltage regulator?

[ChampioNman]

You are correct and the gasket comes with the VR all you need is some gasket sealer to complete the install. Remember you will need 5/16th X 24 thread bolts to secure the puller to the flywheel. Loosen the nut but do not remove and grease the top of the crank shaft so the puller part will not knurl over the thread of the crank. then have fun you will need something to stop the flywheel from spinning though. CM

[DoferGofer]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChampioNman &raquo;</TD></TR><TR><TD CLASS="quote">You can do it but the Flywheel has to come off to get to it and you'll need a flywheel puller for that and a 1 1/4" wrench for the flywheel nut. CM </TD></TR></TABLE>Ditto, been there done that. Piece of cake.

[DoferGofer]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChampioNman &raquo;</TD></TR><TR><TD CLASS="quote">You are correct and the gasket comes with the VR all you need is some gasket sealer to complete the install. Remember you will need 5/16th X 24 thread bolts to secure the puller to the flywheel. Loosen the nut but do not remove and grease the top of the crank shaft so the puller part will not knurl over the thread of the crank. then have fun you will need something to stop the flywheel from spinning though. CM </TD></TR></TABLE>It's called a flywheel turner in the automotive world but, don't many places carry them any more. Try a napa parts store.