1970's 70 hp LooperJet

[thatone123]

Attached Photo. This engine has about 95 psi compression and seems to run with authority except it tens to cough a little than idle down and stop unless I keep it revved up manually. Put some Evinrude tuner through the carbs and they run a little better but still same problem. Hoping I would not have to clean carbs but doable. Does that sound like a carb cleaning issue ? AS to the control cables are these vintage cables the same as to pushing and pulling the same distance? You don't need a shifter cable for a jet so it just has one cable hooked up. I noticed that when I put the throttle forward, the choke solenoid would push out and then go back in and this did not seem right of course. IT will start when I manually choke it, but that solenoid does not seem to work or might the other cable be the better one??? I bet it is hard to find a new solenoid as I have not even found a schematic that shows one.

 

[racerone]

Compression numbers are very low !!-----Looks like some sort of shift is required on it.

 

[StarTed]

I have a similar Evinrude that does use both cables. The shifter moves it from forward to reverse by moving the gate.
.
Have you checked the compression after it ran a bit? That should bring it up some..

 

[thatone123]

Yes, the gate is disconnected from the jet on this one. Many seem to unhook the reverse on jets as they don't use reverse much. I can't see where it would attach. It does not matter to me at this point as long as one of the cables will work to throttle the engine and choke properly. Yes, warming it up will help the compression, so will changing the head gasket.. Wondering if the cough and receding idle is a mixture screw problem on one of the carbs or they need cleaned. Usually Evinrude tuner cleans good but motor is still the same with the cough and idle problem.

 

[racerone]

The parts book for a 1976 model 70 HP does not appear to show a low speed mixture screw !------The cowling is for a 76 model 70 HP.-----But who knows what motor is inside there.-----Model # or more pictures !

 

[jimmbo]

The Transom/Swivel Bracket is 1968 - 1972. 55hp, 60hp, or 65hp

 

[Bosunsmate]

Sort your choke out first, that might explain some of the running problems. Ive one of those solenoids and they are very reliable. Perhaps there is a short in your control box which is occurring when you move the throttle.
To operate it normally you push the key in

 

[racerone]

Looks to be a short shaft too.-----Seems to be a lot of Evinrude blue paint on it.

 

[thatone123]

Wow, all good info...What a outboard...maybe a cannibalized wonder...no model/serial plate...Thinking it is before 76 or 76 as raceone inferred. Yes, it is a short shaft that is certain.

 

[jimmbo]

That looks like the Thermo Electric Choke

 

[racerone]

The power[ack used on it was first used on the 79 models I think.--And no thermo-electric choke in 79-------And the short model never used a tilt tube for steering on them.

 

[StarTed]

The jets use a short shaft engine on a long transom. Mine is a '76 75HP jet but pretty much the same as yours. The choke is activated by pushing in the key. If all 3 cylinders are low compression I'd think the head gasket is fine. One thing to consider is the shaft seal going down from the power head. A leak there could cause idling problems.

My single control has a problem getting and keeping the gate at neutral. It is somewhat worn and does not return to the exact same spot.

Water to a spark plug is an exhaust manifold leak. A common problem with those engines.

Good luck with yours.

 

[thatone123]

Yes, Thanks Star Ted, Raceone and a few others were on the ball as I found the serial plate as it was under a large clamp I had on the stand to hold down the outboard. It is an Evinrude 75 1982 (E75ERCNB) and sure enough it had the wrong hood. Did a lot of testing today with it along with Sea Foam treatment. Runs good at high RMP but at idle does that nasty cough and tries to stop until it does stop...Idles better though.., Any thoughts on these outboards? I am impressed by the power and lightness. Far cry from the weight of the 4 strokes. Star Ted or anyone know where the idle jet is on this? In a schematic they refer to what I think is the idle jet on the top of the carb as an orifice?

 

[StarTed]

My book is ????.

As I recall there is no idle mixture adjustment, just a speed adjustment.

Clean the carburetors and do it again. They need to be very clean to run properly. I think the idle jets are at the top of the carburetor with some of the hole behind a pressed in cap. If ethanol fuel was used or moisture was left in then some white powder could be causing your problems. Blow out the holes with compressed air and carb cleaner several times. They can't be too clean.

Hope that helps.

 

[jimmbo]

You have a frankenrudeson. that Transom/Swivel Bracket is pre 73, it has no holes for bolting the engine to the transom, and requires the Drop In bracket to be mounted to the boat, then the motor is lowered into it, and held in place by two horizontal bolts. Of course there will be some who will say the single hole through each bracket can be used...
The Swivel Bracket is also lacking the holes needed to attach a power trim system, which wasn't available until 73

 

[thatone123]

On the above photo of the motor would the screw right about the throttle cable affect timing

 

[jimmbo]

The Screw directly above where the throttle cable hooks up is the Idle Speed screw. It will affect the timing as that is how the idle speed is controlled. The carbs are fully closed, or they're supposed to be, and by varying how far the timing is retarded is how the idle speed is set.