omc question

**delawarerick** · 07-12-2019, 08:06 PM

I have a 1978 johnson 55hp that will not stop stalling have checked all kinds of things and will not stay running when put in gear. Will not having a thermostat cause this. I have run on the hose as well as put in water and it does not get warm. After 10 minutes no temp on heads. thanks Rick

**Merc 2.5** · 07-12-2019, 08:18 PM

I seriously doubt stats causing prob, compression will tho ,if fuel and spark is gud

**Motv18** · 07-12-2019, 08:53 PM

Check the lower busted gear will kill it every time.

Provided you you went through fuel and spark.

Had a done once that would run in reverse and die in fwd, poor fella had the carbs rebuilt twice and was about to buy a powerpack before I spoke up and said if it runs fine in reverse why would you mess with the engine stuff.

**Instigator** · 07-13-2019, 06:12 AM

Stats won’t do it Rick.

Motv18, is right too.
I rebuilt s powrhead for a customer after his shop told him it was bad.
It was a carry out and he called me after installing it to tell me the gear case was bad and not the p.head ��

**perfmarine1** · 07-13-2019, 06:48 AM

Thermostats can affect your idle that's the reason they are in that motor once you're on plane thermostat is bypassed

**delawarerick** · 07-13-2019, 08:33 AM

gear case is good at least it goes in gear but today I went out and checked compression and it was 200 top and 185 bottom

must be one of them race motors what is going on. This motor was fixed had a hole would timing cause this compression? Carbs are rebuilt fuel pump is good lower good spark excellent. I at the verge of using this motor for target practice I have another 2 cylinder 60 but to change it out is a pita. Thanks Rick
I did notice a bit of play in the throttle arm when you return it to neutral.

**delawarerick** · 07-13-2019, 11:04 AM

Update the choke on this is both manual and electric if I put it on 1/3 the way it runs better. High speed jet or did something come loose and clog the newly cleans jets? I think my compression guage took a crap.

**rochelle howell** · 07-13-2019, 02:41 PM

I've been burned more than a couple times on my old junk by not doing ALL fuel lines when carbs are cleaned/rebuilt.
Being cheap or in a hurry because of having to wait for appropriate sizes of fuel line in ethanol compliant form has caused me headaches more than once or twice!
I've flushed ethanol compliant fuel lines out completely clean when they had date codes only 3 years old on them, only for them to release junk into the fuel system.
Maybe it's just my luck, but I've grown very leary of reusing fuel lines after carb jobs.
At the very least install a slim mercury style filter as close to the carbs as possible and change out all lines downstream from it.
Just a suggestion.

**Dave S** · 07-13-2019, 06:04 PM

De rick is lost in FL.... prob solved,,,,,,,

**delawarerick** · 07-13-2019, 08:41 PM

This motor has a gremlin something is not right gonna pull the carbs again did replace all fuel lines loaded the gun will make a good target.

**flabum1017** · 07-13-2019, 11:00 PM

Originally Posted by delawarerick

This motor has a gremlin something is not right gonna pull the carbs again did replace all fuel lines loaded the gun will make a good target.

They are real sensitive to link and sync... get it right... choking it to make it run better might be floats set too low ot clogged idle circuit, you need a good blow to clear them. (compressed air that is)

**delawarerick** · 07-14-2019, 08:00 AM

I think the link and sync and the throttle arm does not return to the stop. Does anybody got the manual procedure for link and sync on this engine. thanks Rick

**H2OPERF** · 07-14-2019, 11:09 PM

Which motor 55 or 60hp? It should idle at about 1000 rpm in neutral and 750 or so in gear with no carb input meaning the carbs are completely closed so its running on idle timing and idle mixture for idle rpm... all omc's were basically set up this way. I usually loosen the carb pick up roller on the bottom carb and move it out of the way when making the initial idle timing/speed adjustment... basically the rpm you want. The book says about 3 deg for idle timing but really means nothing on an old motor... To set it up first move the roller on the carb away from the cam then adjust the idle stop screw on the throttle arm to get the rpm your looking for...now adjust the throttle cable to hold it on the stop. Next it may be necessary to adjust the idle jets if it has adjustable idle jet carbs to clear up a way rich or lean sneese condition if someone has messed with them....This may change the idle rpm and cause you to go back and re adjust the idle timing again.... once you get all that and its idling good then you can move the roller back over next to the throttle cam lower mark and see if it will align if not disconnect and adjust the threaded plastic fork that goes to the cam so it will align to the lower mark then move the roller away from the cam about .030 of an inch and tighten it.. you want a small gap so the carbs stay closed at idle even if the throttle moves a little .. Hope this make sense to ya, Dave