Logo
FULL SITE MENU

1983 3 cylinder 70 hp, trouble running

T

tthomp1334

Contributing Member
I have what I think is a 1983 3 cylinder out board engine I bought used.

First the water pump would not work, got that fixed and now can not get it to run right.

When the pump was not working it would start right but not idle with out stopping now can only get it to run at about 1/2 throttle, pull it down to idle and it will quit.

Fuel pump working, Has good spark

tried playing with the idle screw with no success.

Could a bad reed be the problem.

Thanks in advance

Milton
 
No. Rebuild the fuel pump (which may be leaking gas into the motor), and it that doesn't do it, rebuild the carbs.

jeff
 
leaning toward the fuel pump. parts will be here tomorrow.

Engine been setting for a while, First time we cranked it it cranked fine just had a little rough idle, The more we ran it the worse it got to the point you had to crank it at 1/2 throttle just to get it to run, back off throttle and it would dye.

Check the plugs and they are wet.

Milton
 
Last edited:
I had a similar problem with my '92 40hp 4 cylinder 2 stroke.

At the beginning of the season, the engine would run OK only over 1500rpms but not idle; harder and harder to start; then, eventually, spark decreased and decreased and eventually quit; plugs were wet and much gas out the exhaust.

I'm no mechanic, but had the shop manual and a multi meter. See my thread at http://www.marineengine.com/boat-fo...68-Yet-Another-Merc-40-2-Stroke-With-No-Spark. There, I verified my electrical components and found the stator was out of spec. Replaced it and engine now runs like it used to. Maybe you can verify yours.
 
Last edited:
Right now I have a good hot spark, Hope I am not disappointed and it not be my fuel pump.

Parts came today and will try to install this evening after sun gets low or tomorrow.

Fingers crossed.

Milton
 
A little disappointed.

First I got the wrong kit and the old one looks good, all one peace with no holes or tears it it.

Can not use it back, Was very careful removing the old one but still broke one of the old gaskets.

The bolts holding the pump together were not very tight, very little pressure needed to remove them.

Ordered the right one this time

????????

Milton
 
Last edited:
Hang in there! At least yours is repairable. I fried my best triple (dumb me) and wore out the other one I've had for years.

Jeff
 
Posted this on rickM46 thread but thought other might he helped with it.

Below is a drawing of my engine wiring

Check the ohms on the two wires Blue and red with meter set on the horse shoe looking symbol and got 16.8 ohms. ???

Tested the red wire to ground and go 165 ohms

Below is the specs for the stator

1980-1983 70 HP
Between blue and red stator leads 5400-6200 ohms
Between red stator lead and powerhead ground 125-175 ohms

Thanks for your help

Milton
 

Attachments

  • stator wiring.jpg
    stator wiring.jpg
    73.4 KB · Views: 38
Regarding the fuel pump, have you tried starting the engine and then continuously squeezing the primer bulb to keep fuel flowing to the float bowls on the carbs?
 
I let this set for a while, some times doing this and coming back to it helps.

Now I get no ohms reading when checking the blue and red wire but have a good blue spark that is over a 1/2"

Is it possible to have a good spark and the stator be bad or do I have a bad meter. ???

Milton
 
I have this meter: https://www.amazon.com/Tekpower-TP2...Power+tp2844r&qid=1568204797&s=gateway&sr=8-1. I also had a freebee meter from Harbor Freight that agreed with the latter meter - nice to have a backup with a little plus/minus.

They showed that my Blu/Wht and Blu leads out of my stator at 18,708 Ohms where the spec was 5700-8000 Ohms; my Red/Wht and Red leads at 95 Ohms where the spec was 56-76 Ohms.

How did you test spark? Some say that the neon spark testers may not be accurate; my neon tester at the beginning of the season showed a very small blue spark and then, later, no spark where my CD lawn tractor and the same tester showed a fat and long orange spark. Some say that you have to be careful on how you test spark to avoid damage to the electrical boxes.

Since you are getting good spark, makes me think your meter is off; maybe verify that with another meter. Nonetheless, while you were adjusting the idle mixture screws, did that have an effect on engine rpms?
 
Last edited:
Will get a new volt meter today and see what happens, If it checks out good will pull the carbs and give a good cleaning.

Thanks
Milton
 
Got a new volt meter and retested the stator with the old and new test meter, Both gave the same reading.

Spec for blue and red are 5400-6200 I get 6.96 ??

Red to ground 124-175 I get 149

Does not make sense when I have a good 1/2" blue spark. ???

What am I missing.

Removed the carbs and broke them down and soaking in seafoam, will have to see what happens when I put them back on the engine.

Thanks for all the help

Milton
 
Aabsolutely. The red wire is the high speed stator coils, where the blue is the low speed. You need another stator. Sorry.

Jeff
 
That was my thought after looking at the carbs, They are spotless just like they had just been rebuilt.

That is why I could get it to run some times when throttle set above 1/2 throttle and would die when pulled back down.

Ordered stator yesterday.

Thanks for your help.

Milton
 
That is the same characteristic of mine - run fine above 1500rpms, very hard to start, die at idle; I lucked out when the spark quit entirely - easy diagnosis; got a new stator made by CDI from marineengine.com; runs great now - idles good, starts easy - always needed 4 squirts of the enrichener while turning over.

Let us know your results.
 
Got carbs installed, That was a job in it self.

Got the new stator today and checked the ohms read the same as the old one with two different meters.

I went ahead and installed it, What did I have to lose.

Engine fire up and purring like a kitten. ??????

Thanks to all for your help.

Milton
 
Back
Top