Motor Not Running Right...

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JGibson
Posts: 237
Joined: 13 Jul 2012, 17:46
Location: East TN

Motor Not Running Right...

Post by JGibson » 05 May 2013, 10:30

I finally got to take my boat out the other day and see how the motor runs. It started great, idled fine...when I started giving it throttle it wanted to start acting like it was missing, I had it at WOT and was barely moving. Every now and then it would try to stop "Missing" and take the gas I was giving it and run right, but it would always go back to "Missing". I pulled the plugs and checked for fire and believe me, they are firing, firing great, my hand will never forget it :shock: After a few minutes of running it out to the end of the small lake and back, it shut down and would not start back. Plugs were still firing, getting gas but no engine start, it would try to start but no go. The motor is a 1976 40hp Johnson. Any ideas of what could be causing this and what I can do to fix it? I hope this is enough info, I hate having you guys read my posts and there not be enough there to describe whats going on...
1979 Monark 1443, 1969 Johnson 18Hp Motor

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muskiemike12
Posts: 553
Joined: 16 Feb 2011, 10:17
Location: Aitkin, Minnesota

Motor Not Running Right...

Post by muskiemike12 » 05 May 2013, 10:48

Did you have fresh gas?

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JGibson
Posts: 237
Joined: 13 Jul 2012, 17:46
Location: East TN

Motor Not Running Right...

Post by JGibson » 05 May 2013, 11:24

Yes. Fresh tank and oil.
1979 Monark 1443, 1969 Johnson 18Hp Motor

dkonrai
Posts: 169
Joined: 07 Sep 2012, 23:26
Location: walnut creek, california

Motor Not Running Right...

Post by dkonrai » 05 May 2013, 11:55

have you cleaned the carb? if yes, did you set the float and change the small washer in the carb?

how old are the points?

also could be a fuel issue, fuel pump and fuel lines.

2 strokes are simple, compression, spark, fuel. check compression, sounds like you have spark (i would still change the points) and fuel (carb, fuel pump, fuel lines, fuel connections)

dino

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JGibson
Posts: 237
Joined: 13 Jul 2012, 17:46
Location: East TN

Motor Not Running Right...

Post by JGibson » 05 May 2013, 14:55

Noticed today that someone has replaced 2 bolts on the intake, the 2 on the bottom are 7/16 bolts while the others are flat head screws. The 2 that were replaced, one of them was loose, tried to tighten it but wasn't able to, I'm thinking it is either stripped or not long enough. Would this be part of the problem? I'm looking into getting a little longer bolt to go back in it. If it's stripped, I have another motor that I can just change everything over to and use it.
1979 Monark 1443, 1969 Johnson 18Hp Motor

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Charger25
Posts: 457
Joined: 31 Jul 2012, 08:01
Location: Aylett,Va.

Motor Not Running Right...

Post by Charger25 » 06 May 2013, 10:13

It's probably stripped, your gonna have to drill and tap new threads with a larger bolt or insert a heli-coil to keep the same size bolt. If the intake is not tight enough to seal it will draw in air causing it to run way lean which is not good.
And like what dino stated, wouldn't hurt to do a compression check.
12ft ryancraft w/ 8 hp Frankenstein rude
14 ft fisher w/ 15 hp rude
16 ft lowe w/ 25 hp Frankenstein rude
9.9 Rude / sleeper
6 hp Evinrude Sail Master

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JGibson
Posts: 237
Joined: 13 Jul 2012, 17:46
Location: East TN

Motor Not Running Right...

Post by JGibson » 06 May 2013, 10:29

Did the compression check, both cylinders were right at 90. I took the fuel pump off and there was something in it (looked like dead ants?). Fuel lines all blown out, I changed carbs with one from the parts motor I have after cleaning it (my father in law has the other one). Not sure how old the points are but they looked pretty new when we first started working on the motor. I have very good spark (checked with a spark tester at 7/16 gap). I didn't get to take it to the lake because of rain yesterday to see how it ran but I did run it in a barrel for a few minutes. Hopefully I will get to the lake today, if I do I will post my results, may try to get some video of it.
1979 Monark 1443, 1969 Johnson 18Hp Motor

MNHunter505
Posts: 178
Joined: 19 Jul 2012, 17:28
Location: Suffolk, VA

Motor Not Running Right...

Post by MNHunter505 » 11 May 2013, 10:41

What were the results? Also, when you say "the points look good" what are you referring to?
1996 Voyager 70 Series 16ft jon boat, 1979 Evinrude 35hp
http://www.tinboats.net/forum/viewtopic ... 21&t=29553

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