Need help--older Mariner 40EL rough idle with bad shaking in gear

TinBoats.net

Help Support TinBoats.net:

SAABologist

Member
Joined
Mar 28, 2022
Messages
21
Reaction score
4
Location
College Station, Texas
I'm no mekaneck, but just my own thoughts... It's a Short Shaft issue.
I have a mariner 40 EL. I deleted the automatic oiling machine and use pre-mix. I think that 50:1 is a bit oily and the plugs do foul in time. If you keep the carbs clean and always have new plugs handy (5 mins to change both) it runs like a workhorse. It's the easiest motor to work on I've seen. I gather from the thread that the original poster had a CDI problem. Now I know what to check if mine starts running badly and plugs is not the fix.
 

cyclops2

Well-known member
Joined
Nov 17, 2022
Messages
129
Reaction score
49
LOCATION
frenchtown N J
A study of engine problems came up with a surprising fact. Most problems are electrical.
 

SAABologist

Member
Joined
Mar 28, 2022
Messages
21
Reaction score
4
Location
College Station, Texas
A study of engine problems came up with a surprising fact. Most problems are electrical.
I guess so! Mine would not start the other day and I think it was an ancient non-marine toggle switch that had replaced the original kill switch. I replaced it with a good kill switch and now it's been fine. Happy boating,
 

thill

Well-known member
Joined
Feb 25, 2011
Messages
490
Reaction score
125
Location
Virginia, USA
Bad kill switches and bad key switches are notorious, as well as corrosion on connectors. Have had a number of customers come to me with an engine they thought was done, and when I unplugged their wiring harness and I plugged in my test harness, VROOM! Started and ran just fine.

I often tell customers who call me to unplug the control and jump the solenoid. If suddenly they start getting spark, they have narrowed down the problem. It's not the motor. That works a good percentage of the time.
 

SAABologist

Member
Joined
Mar 28, 2022
Messages
21
Reaction score
4
Location
College Station, Texas
Bad kill switches and bad key switches are notorious, as well as corrosion on connectors. Have had a number of customers come to me with an engine they thought was done, and when I unplugged their wiring harness and I plugged in my test harness, VROOM! Started and ran just fine.

I often tell customers who call me to unplug the control and jump the solenoid. If suddenly they start getting spark, they have narrowed down the problem. It's not the motor. That works a good percentage of the time.
Thanks for this comment. Pull starting this motor, even cold, is not difficult. How do I bypass the switches so I can pull-start it if necessary? Thanks!
 

thill

Well-known member
Joined
Feb 25, 2011
Messages
490
Reaction score
125
Location
Virginia, USA
Just pull the plug at the end of the control cable. If it still won't start, unplug the kill switch on the tiller, if it has one.
 

SAABologist

Member
Joined
Mar 28, 2022
Messages
21
Reaction score
4
Location
College Station, Texas
Just pull the plug at the end of the control cable. If it still won't start, unplug the kill switch on the tiller, if it has one.
Mine does not have a tiller. Please correct me if I am wrong here---
When you say unplug end of control cable, that would mean disconnecting the wire harness inside the motor?
That is great to know in case ignition switches fail.
Thanks again,
 
Last edited:

thill

Well-known member
Joined
Feb 25, 2011
Messages
490
Reaction score
125
Location
Virginia, USA
Yes, unplug the cable that comes from the key switch. Just remember that if you need to kill the engine, plug it back in. Sometimes it will start when you didn't expect it to.
 

SAABologist

Member
Joined
Mar 28, 2022
Messages
21
Reaction score
4
Location
College Station, Texas
Yes, unplug the cable that comes from the key switch. Just remember that if you need to kill the engine, plug it back in. Sometimes it will start when you didn't expect it to.
Thanks, It is starting instantly and running great now, so I will do some trials with this as a sort of emergency training. I think it dies quickly if I pull the choke.
 
Top