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Third world fix

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la_donna

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"Guru, I have read with great

"Guru, I have read with great interest all of the discussions on the Tohatsu 3.5 4/S. I am suffering what seems a common overheat/stall issue after one year of heavy use while cruising Central America. The engine is used on an 11ft shore boat and is never rinsed out. Warranty work is out of the question here for so many reasons. I seek a third world fix that might get me the rest of the way around the world.
There is only one variable remaining uncovered by you, and my last hope the cooling system is not just weak and in need of constant care. Vapor lock; I am running US winter blend (CA) fuel here in the tropics and, the engine seems not soo hot that I would guarantee it is overheating. Any chance I am vaporizing my fuel en route to the Carb? Any confirmed accounts of this with this model?
Cheers, the crew of S/V Odyle"
 
""I am suffering what seem

""I am suffering what seems a common overheat/stall issue"

One person, repeatedly making an obnoxious jerk out of himself by telling everyone his same BS story, does not make an overheat common. All other cases of stalling seem to immediately disappear when people correctly adjust the angle of the engine on the transom or can be traced to a specific cause. So, if we start of with that as the framework for your problem....
The likelihood of vapor lock occurring would be pretty rare. The only thing finicky about this model is that the engine trim angle has a low tolerance for being off. The cooling system has had no problems of any kind and is just like any other outboard. In a dinghy application chances are that injestion of sand would have worn out the impeller early.

Or the problem might be a true part failure of some kind(ignition), clogged up carburetor or simply bad fuel. Not being able to flush the engine will certainly cause a build up of dried salt/scale that will degrade the engines cooling system, but that would normally take over a year even with no maintenance.

I'll be happy to work with you to determine the cause, but be prepared to spend some time as we go down the troubleshoot list. Is your engine stalling or is it overheating or is doing a combination of both?"
 
"Yes I am a patient person. I

"Yes I am a patient person. I am not convinced the engine is overly hot, this comes from an extensive diesel background. As for transom angle, the unit sat upon the same transom during a very busy season with only periodic stall issues. Now a predictable stall occurs that resolves itself in an hour of sitting.
I thrive in a methodical, step by step process. I have the mechanical experience, all the tools and many 3.5 parts needed aboard with me.
Thank you for the offer to help, not much of a conspiracy theorist myself, besides I cant throw my hands in the air and capitulate. S/V Odyle"
 
"Try changing the trim angle f

"Try changing the trim angle first...The tank position in relation to the draw can change due to weight distribution and wave action. Still stalling? If the stall is predicable you can eliminate the mechanical aspect of the engine as the problem and skip to ignition or fuel. Since ignition is straightforward lets start there first. You need to test for fire when the engine is within the stall zone. If you have fire at that point then the fuel system would be where we would look next. First step on the fuel system is to eliminate the fuel itself as the problem. IE dump your fuel, purge the lines and clean the carburetor."
 
"I was unable to see a spark w

"I was unable to see a spark when grounding the plug to the engine. No strobe aboard and I am loath to grab that electrode while yanking on the cord. Being a diesel person I am at a loss, how can I better confirm the absence of a spark.
Transom position did not change the problem, stalled after 25 Min.
The unit is definitely not overheating; 185 F. in the vicinity of the head, and discharge water is much hotter than ambient temp. of seawater.
Feeling better now I have a few steps under my belt. S/V Odyle"
 
"The field expedient method&#4

"The field expedient method(and that is the one all techs use on this model)is to ground out the plug against the block...Just like you have done. Make sure that the kill switch lanyard is on the kill switch when you do this check. Exercise care as the ignitor, that you are checking, does indeed pack a wallop. Insulated pliers or even a piece of wood to hold the spark plug in place is advisable. It's a lot easier with two people as one can pull while the other gets close enough to see the spark. Early morning or late in the afternoon can make it a lot easier too. If you still have no spark, unplug one lead off the kill switch and try it again. That bypasses the kill switch and we can eliminate it as a source as well. Those are the only two ignition parts. If you have an ignitor failure I will need you to contact me, by email, with your information, so I can replace it for you."
 
"Moving along here, I am conti

"Moving along here, I am continuing to experience trouble confirming spark. In both conditions; stall and running, I cannot see the spark despite assuring a good ground. I will go through the fuel system while awaiting darkness to try again. Even late afternoon tropical sun is too bright. I cannot imagine what type of trouble light/strobe I can construct to improve the dependability of this test, my VOM seems inappropriate. I have confirmed the kill switch is not the problem as the stalling condition persists with this circuit open.
I will update after dark and a good fuel system cleaning. S/V Odyle"
 
"The fuel system has had a com

"The fuel system has had a comprehensive cleaning including fuel replacement, Carb dis-assembly and cleaning , fuel screen and hose cleaning. No effect, still stalls after 15-20 Min. I tested the resistance in the coil while in non-stall mode and found 7.25 Kilo Ohms resistance, in the stall mode the resistance is the same 7.25 K-Ohms. This test was from the plug electrode to ground. I decided upon the coil test after taking the drastic step of holding the lead while pulling the cord in stall mode with out getting popped. Unsure if I was grounded well, as no ground exists on a boat. Perhaps I need to get up the courage to do it again and ground myself to the engine via a ground clip to my ear!
I seem to be running out of tests, is there another resistance test for the coil? Do we need to have a longer talk about transom angle, still a wild shot, given the constant variability of this angle and the predictability of failure regardless of this angle. Is the output of the coil so specific I cannot borrow a coil from a like engine to rule out its culpability?
Thank you, S/V Odyle"
 
"5.5 - 9.5 on the black lead t

"5.5 - 9.5 on the black lead to the spark plug wire.

2 - 3 on the black lead to the high tension wire.

You have to use an analog meter.

If you can borrow a coil off of a like engine frame, Mercury/Nissan/Tohatsu, you can do it that way...But, the simple visual test for spark is all you need to do. If you don't see spark, you have a bad ignitor...What is your engine serial number?"
 
Yes...Your engine isn't re

Yes...Your engine isn't registered though. You would need to contact the dealer that sold it to you and have them register it.
 
"Hello again, Guru. The dealer

"Hello again, Guru. The dealer assures us that our warranty is now registered. Can you help us with warranty replacement of the igniter? We would also like to purchase a spare propeller and three spark plugs."
 
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