2018 MFS20E won't start...

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justind1407

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Hi Everybody! đź‘‹đź‘‹

I'm new to the forum and outboard engines but I'm fairly mechanically inclined.

Recently I purchased a used 2018 Tohatsu MFS20E off Facebook for a great deal to install on my 1540 Jon boat. I assumed there may be an issue with the motor since it was cheap therefore I threw the motor up on a stand to give it a once over before installing on my boat and low and behold I can't get it to start. The motor looks like its never even been ran but I can't tell for sure. It didn't come with a prop and the spark plugs look nearly new so If it was ran it wasn't very long.

First off I disconnected the kill switch and checked continuity with and without the kill lanyard installed and the switch appears to be functioning correctly. Secondly I removed each spark plug 1 at a time and held them to a bolt on the engine block that was unpainted and I don't see any spark. What if anything can I check on these newer EFI motors that may help be do some diagnostics on the ignition circuit. Thanks!
 

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Let's see... If the outboard is not EFI but carbed - put the kill switch to the run position, open the vent on the gas tank, be sure the clean gas tank has fresh high octane fuel in it, prime the gas with the bulb and be sure the hose to the engine is on the up side, pull the choke all the way out, be sure the throttle is in the neutral position and if you haven't stated it recently, which is the case, pull the rope a dozen times and it should start as soon as the gas gets to the carburetor.
If this engine is EFI it must be electric or am I wrong. If it is electric start, put the kill switch in the run position, open the vent on the tank, be sure the gas tank has fresh high octane fuel in it, prime the gas with the bulb and be sure the hose to the engine is on the up side, be sure the throttle is in the neutral position and if you haven't stated it recently, which is the case, push the start button until it fires and it should start right up.
 
Let's see... If the outboard is not EFI but carbed - put the kill switch to the run position, open the vent on the gas tank, be sure the clean gas tank has fresh high octane fuel in it, prime the gas with the bulb and be sure the hose to the engine is on the up side, pull the choke all the way out, be sure the throttle is in the neutral position and if you haven't stated it recently, which is the case, pull the rope a dozen times and it should start as soon as the gas gets to the carburetor.
If this engine is EFI it must be electric or am I wrong. If it is electric start, put the kill switch in the run position, open the vent on the tank, be sure the gas tank has fresh high octane fuel in it, prime the gas with the bulb and be sure the hose to the engine is on the up side, be sure the throttle is in the neutral position and if you haven't stated it recently, which is the case, push the start button until it fires and it should start right up.
This motor is EFI. I'll post another update below after my findings last night...
 
We'll I went and looked at the engine last night again because I wasn't convinced that the ignition system was at fault for my "no start". When I tested the spark plugs for spark a few nights back my wife was manning the pull cord and I guess she wasn't strong enough to cause them to fire. Last night I purchased a spark plug tester and put it inline with the plug and coil wire and could clearly see spark when I was turning the engine over.

Next I will focus my attention over to the fuel side. I sprayed a good shot of starting fluid into the intake and after about 5 pulls it ran for about 2 seconds so I believe I may be on the right track. Someone told me that the fuel rail should be under pressure after priming the hose bulb and I can press the Schrader valve with no release of fuel or air.

Could a replacement fuel pump be next?
 

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My suzuki efi has a low pressure and high pressure fuel pump. The low pressure is mechanical and high pressure is electrical.

The high pressure has a resistance check for the coils..

Engines are probally simular.
 
My suzuki efi has a low pressure and high pressure fuel pump. The low pressure is mechanical and high pressure is electrical.

The high pressure has a resistance check for the coils..

Engines are probally simular.

Interesting. I'll look into this. Thanks for the tip.
 
The primer bulb is not going to be nearly enough to make the injectors work properly. It will probably take quite a bit of cranking on it to get enough of a prime in the system to run, especially if it was dry.

Wouldn't hurt to remove or push in the schrader valve and bleed out all the air first.
 
It should be easy enough to take off the recoil starter off and use a drill with a socket on the flywheel nut to get it spinning good. This would likely be easier to do while holding the schrader open as opposed to pulling the starter.
 
It should be easy enough to take off the recoil starter off and use a drill with a socket on the flywheel nut to get it spinning good. This would likely be easier to do while holding the schrader open as opposed to pulling the starter.

I hadn't thought of this before. Will this damage the engine in any way?
 
I hadn't thought of this before. Will this damage the engine in any way?
Nope, it's just like using an electric start. Just go clockwise looking down from top. There are guys who use drills to start their motors. I'd just be afraid if what happens if the socket "sticks" on the nut when it starts. I imagine it could rip drill from your hand. Since yours isn't starting that should not be an issue.
 
Nope, it's just like using an electric start. Just go clockwise looking down from top. There are guys who use drills to start their motors. I'd just be afraid if what happens if the socket "sticks" on the nut when it starts. I imagine it could rip drill from your hand. Since yours isn't starting that should not be an issue.
Solid info. Makes since.
 
ahhh ha..... the plot thickens... FOOL INJECTION you say eh?.... well that puts a diff spin on it so to speak..
I know nothing about this engine or MANY things actually but have often thought 'zactly how this whole deal works...
specifically EFI with small engines that are NON ELECTRIC START...
so now we got a high pressure pump as well as the low pressure mechanical... wait a minute here.. the high pressure pump is electric ???
wait we got no battery here.. how does the high pressure pump get its electricity ????
I think I heard/read somewhere or from a x brother in law probably over beers that the initial starting pull on the cord generated enough 'tricity
from the rotor/stator part of the flywheel to kick start the electric high pressure fuel pump ??? sounded at least possible to this gringo...
if that is the case.. the drill-socket method might be the only way to verify that fuel is coming to the rail-schrader valve...
good luck... love this site...
 
ahhh ha..... the plot thickens... FOOL INJECTION you say eh?.... well that puts a diff spin on it so to speak..
I know nothing about this engine or MANY things actually but have often thought 'zactly how this whole deal works...
specifically EFI with small engines that are NON ELECTRIC START...
so now we got a high pressure pump as well as the low pressure mechanical... wait a minute here.. the high pressure pump is electric ???
wait we got no battery here.. how does the high pressure pump get its electricity ????
I think I heard/read somewhere or from a x brother in law probably over beers that the initial starting pull on the cord generated enough 'tricity
from the rotor/stator part of the flywheel to kick start the electric high pressure fuel pump ??? sounded at least possible to this gringo...
if that is the case.. the drill-socket method might be the only way to verify that fuel is coming to the rail-schrader valve...
good luck... love this site...
I've come to the conclusion its some strange combination of voodoo magic and sorcery that supplies the initial jolt to fire the high pressure fuel pump on these battery-less engines.

I tried the drill method last night with no luck in getting fuel to the injector rail. I'm going to tear into the vapor separator canister this weekend and see what I find. The high pressure fuel pump resides inside here and my research tells me that since this thing has sat for a couple of years it's locked up from old ethanol gas. Trying to source a replacement motor currently...


Tohatsu part number 3RS043020 for those who may need one in the future.
 
The troubleshooting tree is for my Suzuki DF9.9. It may give you some ideas.

Also, fuel pressure for mine at cranking speed or Idle is 43psi.

Alos a basic power generation for manual start.
 

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