I tried locating the older topic I started on this motor but search didnt work for me.
On the hose, it would idle fine and a variety of RPM ranges but as soon as I put it under load it was tough idling and would not accelerate. In fact it would cough, choke, sputter and most likely quit. I found a bad coil and replaced it…the idling was no longer an issue but it still wouldnt accelerate. The compression was at or near 5 psi but now it is at 84-90 (which makes a LITTLE bit of difference 
).
Chris V advised that I check the WOT timing which was actually first on the list in my maintenance manual for this 1982 two stroke dream. I went on leave for a week, just got back last night. Today went out to accomplish the timing. I quickly discovered something that I should have notice a very long time ago. The timer base was stuck and would not move with the throttle arm!!! So, I sprayed liquid wrench, removed the control rod, moved it back and forth about 3,000 times…hooked control rod back up and moved it with shift/throttle control. Timing is good and will water test tomorrow AM
Thanks Chris and others for helping me through this wonderful project
Mike
12’ Jon boat twin 300 Verados
It runs 80% better. Got it to plane, although it was very slow to do so. At full throttle it would surge like it would lose spark in a cylinder or two or like there was a fuel restriction…maybe both. I have thoroughly checked out the fuel system from tank to carbs, no leaks. Maybe high speed jet clogged. I also use multi meter to check resistance for power pack (according to the procedure set forth by the maintenance manual) and they both checked out good. Like mentioned earlier I did find a bad coil, replaced it. So, not sure what this surging could be. Any ideas? As always, thanks!!!
Mike
12’ Jon boat twin 300 Verados
Groen,
I have a 2000 johnson 150 that could not get to WOT. Research led me to change out the neutral shift switch. It is designed to cut power to cylinders in order to make for softer shifting, less wear on the lower. It was stuck and not functioning. Just a thought as it may be intermittently not working causing your power surge.
Ahhh…ok, I was unaware of a neutral safe switch. Well, this is a 1982 motor so not sure if it would have that but I will definately look in my manual and find out. Thank you very much for the idea!
Mike
12’ Jon boat twin 300 Verados
Are the carbs synched properly? Butterflys closing completely at idle and all opening together thru the range until 90 degrees at WOT?
Rick
When I have the cowl off, the butterfly valves appear to be making the full range of travel in synch with each other. It is probably something to do with the carbs and the timing though…or fuel delivery. Havent had a chance to monkey with it in the last couple of days…will be jumping on it this weekend, I am tired of not being able to fish!!!
Mike
12’ Jon boat twin 300 Verados
with the carb cover off and the cowling removed,
go to WOT on the trailer with just the back of the boat in the like, as if you were driving the boat on the trailer, just a little less boat in the water, so it cant move around.
it shouldnt turn much more than 3500rpms like this, but if you give a little squirt of fuel into each carb throat, it will tell you if you are running lean, rich, or just right.
rich, it wount do anything
lean, it will pick up a few rpms
just right, and it will bog down
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PS
you still need to check WOT timing, and carb synch
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