1978 Evinrude 70HP- Trouble starting/idling/bogging under load

[saltchuckmatt]

Funny....well I brain fart myself quite often, welcome to the crowd!

 

[tphoyt]

Wow what a day

 

[evinrude2323]

Tough one for me to stomach here boys haha not living this down

 

[tphoyt]

Don’t sweat it. It happens

 

[saltchuckmatt]

Choke is for start up only....on a two stroke you want it off right away.

Assuming it's an electric and manual choke maybe the solenoid is sticky.

You push the key in while turning to activate a electrical choke.

Not sure what you have.

 

[evinrude2323]

Choke is for start up only....on a two stroke you want it off right away.

Assuming it's an electric and manual choke maybe the solenoid is sticky.

You push the key in while turning to activate a electrical choke.

Not sure what you have.

Mine has a push key choke. So I guess I need to keep the carb gates open all the time and then only choke it using the pressing of the key? Key will do the choke and that’s all?

 

[racerone]

That lever is for manual operation of the choke.----Used when you need to start the motor with a dead battery.-----These plates close when operating the electric choke switch.-----Time to get an owners manual or get someone to teach you about this motor.----You do not want to be educated through an empty wallet.----Learn how to work on this motor as there are fewer and fewer shops that will work on them.---If you do find a shop it might shock you as to what simple repairs cost.----And best to install a new water pump impeller.---Or at least test the overheat warning horn.

 

[saltchuckmatt]

Yes testing the overheat system and many other things are a must.

 

[evinrude2323]

That lever is for manual operation of the choke.----Used when you need to start the motor with a dead battery.-----These plates close when operating the electric choke switch.-----Time to get an owners manual or get someone to teach you about this motor.----You do not want to be educated through an empty wallet.----Learn how to work on this motor as there are fewer and fewer shops that will work on them.---If you do find a shop it might shock you as to what simple repairs cost.----And best to install a new water pump impeller.---Or at least test the overheat warning horn.

Awesome information. I have a manual on order and it’ll arrive e in a week. I plan to just get spare parts for this thing and take as good of care of it as possible for the rest of its days. I have rebuilt other engines in the past but on 4stroke motorcycles. I will definitely be getting in the weeds once I get my manual. Love working on this kind of stuff and any information is welcomed. I will likely pull the head and inspect. Maybe pull the whole power head and get new gaskets in there. I think you all mentioned 140 compression, I will retest as I most likely was doing the test with the carbs closed. I will likely just do a rebuild for the heck of it and to learn about them. I’ll keep posting pictures, but I may have to get this thing on the water again to test it out.

 

[evinrude2323]

Yes testing the overheat system and many other things are a must.

How do I go about this test? And what other things?
Fuel pump, head gasket, piston condition and cylinder walls, carbs are thoroughly cleaned, I’ll order a new impeller.

 

[saltchuckmatt]

I strongly disagree. The motors running good just replace all the maintenance items and there's not a lot. Gear oil, yearly. Spark plugs, when they're needed. Numerous grease points including the prop shaft. Any kind of fuel lines that don't look good, and water pump impeller or entire water pump kit every 5 years or so. Learn how to grease the prop shaft when the lower leg is out. (Gearcase)

Older Evinrude gaskets last a crazy long time. Be sure to winterize it and right now after you test out the warning system I would just take that motor out on the water and run the crap out of it.

I personally think your compression is fine. Don't make more out of this than it really is.

In my opinion the difference between two strokes and four strokes is the two strokes are the happiest when they're in the upper RPMs!

 

[evinrude2323]

I strongly disagree. The motors running good just replace all the maintenance items and there's not a lot. Gear oil, yearly. Spark plugs, when they're needed. Numerous grease points including the prop shaft. Any kind of fuel lines that don't look good, and water pump impeller or entire water pump kit every 5 years or so. Learn how to grease the prop shaft when the lower leg is out. (Gearcase)

Older Evinrude gaskets last a crazy long time. Be sure to winterize it and right now after you test out the warning system I would just take that motor out on the water and run the crap out of it.

I personally think your compression is fine. Don't make more out of this than it really is.

In my opinion the difference between two strokes and four strokes is the two strokes are the happiest when they're in the upper RPMs!

Hell yeah! Sounds like I’m ready to boat! Next step is asking you guys about replacing aluminum rivets haha I will get this thing out tomorrow if I get the weather for it and it passes the overheating test. I will figure out how to do that test.

 

[tphoyt]

Were the chokes closed on your first test run
that caused this post?

 

[evinrude2323]

Were the chokes closed on your first test run
that caused this post?

I hadn’t messed with it until today so I am assuming so. It did idle the first time I took it out and with chokes fully closed that seems wild.

 

[evinrude2323]

 

[evinrude2323]

Where is my overheating alarm?

 

[racerone]

The buzzer is in the control box at the helm station.

 

[saltchuckmatt]

The alarm sensor, which is just an automatic switch that grounds the horn located up at the box or dash when your motor reaches 145 to 150 degrees, is located with the right arrow. Pull apart the black rubber cover on the wire or stick something long and skinny that's metal in it and ground it to anything on the motor with the key on.

If it doesn't chime out then you must "hot wire" the small horn (buzzer) that's in the control box or under the dash to test that it's working.

Assuming you have a white control box with a rather large red plug back at the motor?

 

[evinrude2323]

The buzzer is in the control box at the helm station.

The alarm sensor, which is just an automatic switch that grounds the horn located up at the box or dash when your motor reaches 145 to 150 degrees, is located with the right arrow. Pull apart the black rubber cover on the wire or stick something long and skinny that's metal in it and ground it to anything on the motor with the key on.

If it doesn't chime out then you must "hot wire" the small horn (buzzer) that's in the control box or under the dash to test that it's working.

Assuming you have a white control box with a rather large red plug back at the motor?

Assuming you have a white control box with a rather large red plug back at the motor?
- where should I take a picture to show you?

 

[racerone]

Slide rubber boot back to expose the metal connecter.-----Turn key to on.----Touch metal connecter to ground.----Horn should sound.----And no need to open throttle to do a compression test on that simple motor.