1973 Evinrude 85 HP fuel,running prob help please?

[triathloner]

I have a 1973 Evinrude 85 HP model 85393m. there are actually pretty low hours on this boat as it sat for a number of years until a couple of years ago. Well it's extremely hard starting, I have to choke it and crank for a long time, like a couple of minutes and it will start to fire and then eventually run fine. It seems it isn't getting gas. I cleaned both carbs, replaced gaskets and jets and such. But I'm pretty sure it's a fuel flow problem, I can prime the bulb and crank on choke for like 30 seconds or more and then pull the plugs and they are dry. Now once it is started, I can run all over the lake full throttle half throttle, and even slow and it keeps running fine, now dog down in power but if I shut it down for a good 10 or 15 minutes it won't restart without a lot of cranking again.

So I'm thinking fuel pump? But would it run good once started if the pump was bad. I've tried different gas tanks, and even put on a new fuel line/ primer. Plus pumps seem to be spendy, like $100 bucks, is there anyone that has a reasonable price on these.

All the gas lines are good, no dry rot, clamps are in place and snug. I suppose I could take the line off the pump that goes to the motor and see if there is a vacuum on that while cranking.

Any thoughts, tips, etc? I would really appreciate it, and my family would like to get out on the water again. Thank you

 

[Les Robb]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

That's weird for sure, you prime which fills the float bowls and when choking it should start or hit at once. Have you tried having a helper pump the primer ball while you try to start normally. It may be the pump just dosen't have the pull at crank speed to give you a fuel flow. My guess would be a vacuum leak between pump and and tank. But you know all about guesses like opinions and all and everyone has one.

Good luck hope you get it solved

 

[triathloner]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

Good idea to have someone pump it while cranking, I'll try that. I was planning on checking for vacuum leaks tomorrow. Thanks for the ideas.

 

[KDT1961]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

Fuel flow or spark. Sounds like your pump may not be pulling enough vacuum at cranking speed, but if you primed your carbs, it should hit anyway.

I have the same fuel pump on my 1976 Johnson 75 hp as you do, and I eliminated the fuel pump as the problem with my motor bogging by rerouting the fuel supply from the screw on cover on the front of the fuel pump directly to the carb. This bypasses the fuel pump altogether. For this procedure, the fuel line goes from the gas tank to the connector on the motor housing, and from the connector on the motor housing directly to the carbs. This procedure was recommended to me by the Johnson repair place that I buy parts from, prior to me dropping $100 for a new fuel pump. My wife pumped the bulb to keep the carbs filled while I ran the motor, and my problem remained, which meant it wasn't the fuel pump. In my case it was pinched lines at the carb.

Another problem could be sticking or incorrectly set float in your carbs. You said you cleaned your carbs, but did you rebuild them?

Another problem could be your sparkies. The original spark plugs for your motor were the UL77V, which were gapless plugs. They were superseded by the Champion L77JC4. Do not use the QL77JC4 as they have the wrong resistance for the older motors. Use the L77JC4 even if you have to order them, don't believe the cross reference sources at the autoparts place. Most say to gap at .030, but my service manual says to gap at .040 (1976 Johnson 75 hp).

Just my nickels worth.

 

[tashasdaddy]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

read, compression, ethanol, outboard won't start and carb cleaning. http://forums.iboats.com/showthread.php?t=299680 also read this. http://forums.iboats.com/showthread.php?t=225510

have you checked compression, should be 100 psi or better. low compression, makes for hard starting. are you getting good spark on all cylinders?

 

[F_R]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

read, compression, ethanol, outboard won't start and carb cleaning. http://forums.iboats.com/showthread.php?t=299680 also read this. http://forums.iboats.com/showthread.php?t=225510

have you checked compression, should be 100 psi or better. low compression, makes for hard starting. are you getting good spark on all cylinders?

Agree, check compression, but I'll bet you have ignition problems, nothing at all to do with the fuel. Those motors were well known for the charge coils on the stator melting down. "Charge" referring to charging the power pack, not charging the battery.

When they are bad, if will have poor or no spark at cranking speeds with the spark plugs in, but will have outstanding spark at cranking speeds with the plugs out.

Hunker down and look up under the flywheel and take a look at the stator. If the two large coils are melted or soft and gooey, there is your problem.

 

[tashasdaddy]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

agree.

 

[ezeke]

Re: 1973 Evinrude 85 HP fuel,running prob help please?

The series 1973-1977 has always required that the chokes be 100% absolutely fully closed for a cold start. It is critical that you remove the air silencer and observe the choke plates as the engine is cranked, to be sure that they close and stay closed until you release them. If the plates are perfectly synchronized, you just need to move the choke solenoid in small increments to adjust.

It is equally critical that the warmup lever is fully used because that advances the timing for the cold start.

Finally, the engine must turn 300 RPM for your CD system to perform at its best; that requires a fully charged powerful battery, good cables and solid connections.