'89 Johnson GT 150 - Won't Past 3000 RPM, Surges..

[Firefox11]

Re: '89 Johnson GT 150 - Won't Past 3000 RPM, Surges..

I looked up the diode online and found it was a replacement just in another manufacturer, so I installed it and it worked like a top!!!!! I have not had a chance to take it out to the lake yet, this afternoon I will. But IMMEDIATELY once it warmed up it sounded and ran different. Acceleration is MUCH quicker and smoother!

If someone is reading trying to resolve this problem here are a few things to look for.. The diode is wrapped in heatshrink tubing in the middle of the wiring harness. The red connector is the harness where the diode is, but I found the diode on the top of the engine burried in the harness. You have to cut the covering off the harness (Careful not to cut any wires) to locate and expose the diode that is wrapped in heatshrink tubing. (About 3-4" long) You have to cut the heatshrink tubing off to expose the diode. What I noticed BEFORE I cut the heatshrink tubing was brown electronic goo coming out of both sides of the heatshrink tubing. I did NOT think a little diode that size would leak that much goo, but it did. Once I cut the diode out under a magnifying glass I could see the diode cracked. Before you solder in your new diode, make sure and put a 3-4" strand of heatshrink tubing back on the wire to cover the diode. It makes it look stock, and protects the diode.

Special Thanks to Iboats.com, Greg E, NYMack and endsapmgr for your assistance. It got me in the right direction for a touchdown!!! Now I must go and play with my toy!! Woooohoooooooo.. God bless

Brent..

 

[Greg_E]

Re: '89 Johnson GT 150 - Won't Past 3000 RPM, Surges..

Glad to here it's running better. The diode you chose isn't that critical, as long as it's close the the same specs. I found one at Radio Shack. It wasn't an exact match but it works fine.

The goo that you found was from the shrink tube. It is adhesive lined. Most marine supply stores sell that type of shrink tube. When the tubing is shrunk, the glue melts forming a waterproof seal.

After you run it check the two plugs that were black and sooty and see if that problem has cleared up.

The OEM manual for you engine should be 507757, but double check that before you order one. There was only one used one listed on Ebay but keep checking.

Now get that horn fixed ASAP. Your rolling the dice every time you run the engine without it.

 

[Firefox11]

Re: '89 Johnson GT 150 - Won't Past 3000 RPM, Surges..

Thanks Greg, that manual is exactly what I need to get next.

The boat would accelerate past 3k now, but I made a mistake and didn't set the timing before I left. With the diode replaced the timing was advanced so much it was spitting at idle. Luckily the spring in the armature the advances the ignition wasn't pulling forward to advance the ignition more, so I was able to run it around the lake and fish it. (Small lake!) It wouldn't rev past 4k, but I was running 40mph. Good enough until it gets tuned up! So now I need to set the timing, do the synch. Wish I had that manual now. I can do it with my sorry manual, but I will have a OEM manual for it soon.

After fixing the tuning issue on the motor I'm going after the horn. Is there a "Easy" location for someone to disconnect the warning horn besides in the remote? I have the old remote with the key in the remote unit. So I'm sure the horn is that little "4 hole circle" on the remote side. I will be going after that as soon as possible as well, but since I will be back working on the tuning of the motor I was gonna keep an eye out for a disconnected wire "I.E - sounder horn disconnected". So any ideas would be good. Its a VERY well taken care of motor, so I would be surprised to find a wire disconnected.

Once again, I really appreciate this site. My pops was completely shocked that that Diode caused that problem!! he said (72yrs old ya know) "I would have NEVER thought that was the problem" Hehehehe.. Touchdown! God bless..

 

[Greg_E]

Re: '89 Johnson GT 150 - Won't Past 3000 RPM, Surges..

I haven't worked on your style remote control, but looking at the wiring diagram the tan wire runs through the big red plug and terminates at one of the horn terminals. The other horn terminal is connected to ground on one of the ignition switch terminals. I don't see any other place to disconnect it.