1985 70hp Evinrude fuel delivery prob.

[DEADDUX]

I recently bought a 1985 1860 with a 70 hp evinrude knowing the boat would need some work. The boat sat for 2 yrs before I got it. The motor originally had VRO, but it has been removed. The engine was gone through before I got it by a mechanic. I have made progress in geting the motor to run right, but it still wont run under load. It will start fine and idle good the first try. When in gear, it will go about 5 mph and die out when you drop the throttle down. It will then get tougher to start back progressivily. It eventually will only run with full choke and stall when put in gear, then it wont start or run until you let it sit a few minutes.


The motor came with an electronic fuel pump that was not attached. It had been installed by the owner two before me. The guy I got it from said his mechanic said it did not need the pump, so he took it off. I dont know if it was run in water after he pulled the pump. I saw it run on the hose pipe.

Here is what I have done:

I put new fuel line from the tank to a brand new Mr. Gasket electronic fuel pump 5-7 psi. I put an open connection on the tank (not the barb kind) and attached the line with hose clamps. The hose did not fit tight to the connector, so I tightened the clamp down as hard as I could without breaking the clamp. I have the same connection going into the pump filter and out the other side of the pump. The motor connection is brand new and the barb style. From tank to motor my lines are 3/8". From inside motor to carbs the lines are 1/4" then drop to 1/8" as it branches to the high and low jets on the carbs.

I also pulled the carbs and cleaned them. They had new gaskets on them and the floats looked good. I sprayed out the jets with carb cleaner. I set the bottom of the floats to the top of the bowl by eyeball.

I also put a new set of spark plugs on it. Compression is 140 on all 3 cyl. Spark is good on all cyl.

My Plan:

I have ordered 3 carb kits w/o floats. I am going to replace the jets and gaskets to be sure. I am also going to replace the fuel lines from inside engine to carbs. While in there, I am going to check the reeds on the manifold. I forgot to do that last time.

Question:

1) Do i need 3/8" line from tank to motor if it stepping down to 1/4" inside the motor anyway? I can get a better seal on a 1/4" by changing the fittings.

2) What would the motor do if I had a bent/ broke reed?

3) I am thinking it is not power pack or timing because it idles good at high and low. Is this correct?

4) my pump is around 4-7 psi. Is this sufficient or too much?

5) How precise do the floats have to be to run right? Will a 1/16 or 1/32 difference between carbs make it not run right?

6) any other ideas would be greatly appreciated.

thanks,
mike

 

[jtexas]

Re: 1985 70hp Evinrude fuel delivery prob.

Couple observations about your new electric fuel pump.
1. Marine electrical parts are shielded to prevent throwing sparks (because boat fuel tanks are vented to the atmosphere), and to protect from corrosion. Automotive equipment does not last very long in the boating environment.
2. Unless you installed a circuit that shuts off the pump when the motor quits (whether or not the key is on), if your carb float valves wear out (which they will eventually), and you forget to turn the key off when you stop the boat (and you will sometimes), you will have a gasoline fire on your boat. It won't be pleasant.

The vacuum operated fuel pumps are incredibly reliable and cheap & easy to repair. It would cost you about $100, though.

1> Yes, use the 3/8 hose. There are no fuel lines between the high and low speed jets; the jets are all inside the carbs. You may be refering to the feed from the #2 carb to the top & bottom. OEM fuel feed between carbs was 5/32". I replaced mine with 3/16 and no problems. I suspect you're ok with 1/4 inch. 1/8 might be pushing it.

2> The carbs would be spitting up fuel. More than just the occasional fine droplets.

3> If spark will jump a 7/16" gap on an inline tester clipped to the engine block, then ignition components (including powerpack) are fine. If you haven't pulled the flywheel, timing is most likely fine, too.

4> Don't know. I think the OEM vacuum operated pump is best.

5> Make the floats hang parallel with the carb body when held upside down. Precision is paramount. If they're off one way it'll flood. If they're off the other, it'll misfire at high speed.

Agree that your next step is carb rebuild. Note that you won't be replacing the jets, but you will replace the float valve needles and seats.

Read the "Carb rebuilding" thread in the "engine FAQ" section of iboats. And, I highly recommend the factory shop manual. It will walk you through the link & sync procedure which you will need to do after reinstalling your carbs.

welcome to iboats!

 

[DEADDUX]

Re: 1985 70hp Evinrude fuel delivery prob.

1> Yes, use the 3/8 hose. There are no fuel lines between the high and low speed jets; the jets are all inside the carbs. You may be refering to the feed from the #2 carb to the top & bottom. OEM fuel feed between carbs was 5/32". I replaced mine with 3/16 and no problems. I suspect you're ok with 1/4 inch. 1/8 might be pushing it.

2> The carbs would be spitting up fuel. More than just the occasional fine droplets.

3> If spark will jump a 7/16" gap on an inline tester clipped to the engine block, then ignition components (including powerpack) are fine. If you haven't pulled the flywheel, timing is most likely fine, too.

4> Don't know. I think the OEM vacuum operated pump is best.

5> Make the floats hang parallel with the carb body when held upside down. Precision is paramount. If they're off one way it'll flood. If they're off the other, it'll misfire at high speed.

Agree that your next step is carb rebuild. Note that you won't be replacing the jets, but you will replace the float valve needles and seats.

Read the "Carb rebuilding" thread in the "engine FAQ" section of iboats. And, I highly recommend the factory shop manual. It will walk you through the link & sync procedure which you will need to do after reinstalling your carbs.

welcome to iboats!

thanks for the advice. this is an awesome site. I have been lurking for a while and used the search on here a lot, trying to learn.

I have worried a lot about the electric pump for safety reasons. I hunt a lot of ducks and am hard on a boat. I have worried about something hanging it and it pumping fuel to the boat, especially with dogs going in and out. I have it wired off the motor, where when i turn the key it pumps. I definitely need to rethink that.

My buddy gave me a bunch of parts from when he had a 3 cyl evinrude. He says it was basically the same engine as he had. I think it was a late 70's. Would the pump work on this one? They were both 70 hp. I could not find where it would bolt up, so i did not put it on. I am guessing that is because mine was set for VRO???

 

[jtexas]

Re: 1985 70hp Evinrude fuel delivery prob.

Does that pump look similar to the one pictured below? if so it'll work. Part #9 in the diagram is the feed to the carbs, and #11 is the pulse line. If it still has the original diaphram, it might not be resistant to ethanol-blended fuel. Rebuild kit about $11 on iboats, you'll need the part number to ID the right kit.

It'll fit in the space where the vro pump was; you might have to improvise a little, but the mount isn't mission-critical. You can probably get some direction from the forum by searching for VRO conversions. OEM spec for clamps with these pumps is tie straps; I just use cable ties (a good quality name brand, the cheap ones are prone to breaking).

I wonder if the tach sender could be used to switch on a power transistor to run an electric pump? It would have to rectified........ just a thought.

 

[DEADDUX]

Re: 1985 70hp Evinrude fuel delivery prob.

The fuel pump i have is the same as in your pic. Thanks for the help man. I am going to get a kit and return the electric pump.

mike

 

[jtexas]

Re: 1985 70hp Evinrude fuel delivery prob.

see below, where it goes & how it's mounted on a non-VRO motor. Two of those bolts go through the housing and screw into the exhaust manifold. or a bracket affixed to the manifold.

 

[patrick4266]

Re: 1985 70hp Evinrude fuel delivery prob.

if you can find a old motor you can take the bracket off of that. I had a old 1976 70 hp laying around took the fuel pump, rebuilt it, and took the bracket off and it bolted right up and I have the same motor as you.

 

[DEADDUX]

Re: 1985 70hp Evinrude fuel delivery prob.

Thanks for the help guys. It was good talking to you Patrick. Glad to know that fuel pump jtexas is showing will work on an '85. I am pretty sure I found where the pulse line connects, but it is tough to tell if you dont know what you are looking for. There are no hose fitting on the manifold on that side, but I think i can tell where one used to be.

 

[patrick4266]

Re: 1985 70hp Evinrude fuel delivery prob.

It's below the starter, if you don't figure it out by tomorrow, I will email you a pic of it.