1985 Johnson 150 idle surge

[Bimmerdad97]

2 weeks ago we bought a 2001 skeeter fish and ski boat with a 150 Johnson vro the previous owner swapped the Johnson onto it and had it running for a while, well one day it stopped running and he put it up for sale saying the carbs had a piece of grass in them? We bought it thinking it would be an easy fix and it’s turning into an expensive mess, I’ve rebuilt the carbs, replaced all the fuel lines and we even replaced the ignition timer based on the ohms being out of spec. Tonight we got it to somewhat run but it surges really heavy like whoa, whoa, whoa. No kidding that’s what it sounds like lol we’re now completely lost with this thing! Any help would be kindly appreciated! Attached is a link to the video of how it is running.

 

[saltchuckmatt]

Sounds like it started to idle correctly right at the end.

Anyhow, did you do a compression check before purchasing it? If so post those numbers.

 

[Faztbullet]

Ignition problem.. start by disconnecting the harness and then jump starter. If it runs OK the problem boat side. Also you will need primer on to kill it or rags stuffed into carbs if you do this. Check the voltage from stator to packs and if you bought a CDI brand timer check Amphenol pins in connectors as they are bad about not being fully inserted.

 

[Bimmerdad97]

Ignition problem.. start by disconnecting the harness and then jump starter. If it runs OK the problem boat side. Also you will need primer on to kill it or rags stuffed into carbs if you do this. Check the voltage from stator to packs and if you bought a CDI brand timer check Amphenol pins in connectors as they are bad about not being fully inserted.

Thank you for giving me some ideas and I’ll definitely check the pins tonight!

 

[saltchuckmatt]

Surging is typically a fuel issue so your not out of the woods diagnostic wise.

Past owner said piece of grass? Compression check before spending anymore time on this engine.

 

[Bimmerdad97]

Surging is typically a fuel issue so your not out of the woods diagnostic wise.

Past owner said piece of grass? Compression check before spending anymore time on this engine.

Yeah grass lol. I was also considering the Fuel Pump being put on the wrong way. And I do need to compression check, but the engine runs fine every once in a while.

 

[racerone]

Use timing light to see if and where there is a spark issue.----Switch powerpacks and check again.----See if issue stays or moves.

 

[Bimmerdad97]

Use timing light to see if and where there is a spark issue.----Switch powerpacks and check again.----See if issue stays or moves.

Could the power packs be intermittent?

 

[racerone]

They are electronic goodies.----So yes there can be poor connections / broken wires.----Do you know what a powerpack does ???-----So switch powerpacks and do your testing.-----Nobody can do that for you from 999 miles away !

 

[Bimmerdad97]

They are electronic goodies.----So yes there can be poor connections / broken wires.----Do you know what a powerpack does ???-----So switch powerpacks and do your testing.-----Nobody can do that for you from 999 miles away !

I’m very new to outboards but I’m assuming they hold power for the coils to fire??

 

[racerone]

Note ----The battery is not used to make voltage to fire the sparkplugs.----All done by the spinning flywheel and electronic bits.----There are numerous wires and connections that could be faulty.----Causing the intermittent spark.

 

[Crosbyman]

I’m very new to outboards but I’m assuming they hold power for the coils to fire??

first thing to do is get yourself a good service manual and do some reading ... UTUBE has lots of videos for you etc...

 

[jonesg]

They are electronic goodies.----So yes there can be poor connections / broken wires.----Do you know what a powerpack does ???-----So switch powerpacks and do your testing.-----Nobody can do that for you from 999 miles away !

this is the troubleshooting i would try, see if the problem follows a pack.
i would also revisit the scene of the most recent service and look at the carbs.
did the PO rebuild all or just the one.
junk in one could be the same for all of them. examine the filter, replace with new and open the old one. examine the airbox for grass clippings etc.
remove and blow the airbox out with airgun.

in the absence of a smoking gun...its probably elec.