73 Evinrude 65 Dies Under Load

[Vivii]

This is my first post on the site. I have been getting a lot of good information reading others posts but now am stuck.

I have a new to me 73 evinrude that I don't know a lot about the history other than like everyone else, was told it ran great before. It will start up and idle/ rev on muffs even in gear but once in the water, it will die once it is in gear. You can ease into the throttle and there is a sweet spot that it will run about 5mph but nothing more. If you go higher sometimes it will surge like it wants to go, but will eventually die. We have replaced the gaskets on the exhaust/ cooling side because if a small leak as well as a new head gasket/ thermostat. All 3 carbs have been removed, cleaned, and rebuilt. All fuel lines have been replaced along with the fuel pump except the main line from the tank to the motor and the bulb. The tank and that line/ bulb looked newer when we got the boat. The compression has been checked and was between 135-138. The throttle cables have been replace, throttle cam adjusted per the 4 31/32" requirement, roller set of from the cam but the mark centered when no throttle is applied, and the spark advance lever moves freely.

I am completly lost on where to go next and dont want to keep throwing money at it with no fix... can anyone help?

 

[boobie]

Will the spark jump a 7/16" open air gap on a spark tester ??

 

[racerone]

Fact------In gear on muffs is the same as neutral !!----The prop does no " WORK "----Sounds like it is running on 2 of 3 cylinders.-------Did you remove the high speed jets that are screwed into the float bowls ?----Those can fool you into thinking the are clean.

 

[Vivii]

Will the spark jump a 7/16" open air gap on a spark tester ??

I haven't checked the spark jump but will today. I will have to pick up a spark tester.


As far as the high speed jets, I removed them and the low speed jets when I did the carb cleaning. They all got soaked in acetone over night and then I ran a brush through them and blew them out.

 

[Vivii]

I got a chance to test the spark and all 3 sparked great across 7/16", nice dark and blue. We checked the cab sync and it looks good. Tried another tank and fuel line/ball that is known to work and still nothing. When we were on the water, if we put it in gear we could manually control just the throttle at the carbs and it would rev up and run great. Any ideas on what to go to next?

 

[racerone]

Perhaps check the flywheel key.

 

[oldboat1]

in addition --

When you rev by opening the carb flaps, you are not operating the carbs in unison with the timing plate -- hard on the engine and potentially dangerous (would be more so on muffs with no back pressure). Does the timing plate turn when you operate the remote throttle lever? Maybe the remote throttle cable is not anchored at the engine or is other wise slipping.

 

[Vivii]

Yes it does, both the spark advance lever and the cam operate. The spark lever moves until approx 25% of the throttle, maybe a little less then it hits the stop and the cam takes over to operate the cab flaps solely. When we operated it by hand, we moved the throttle sync knob (that touches the cam) so all 3 carbs opened at the same time i think, but we didn't do more than long enough to see it work.

What/where is the flywheel key and what should I check on it?

 

[oldboat1]

Pull the flywheel. Key is in a slot in the shaft. See if it's there and undamaged.

 

[Vivii]

I noticed that where the gas line from the tank comes into the motor there is a gap at the connections, should this be this way or could this be pulling air? Also should the engine side of the connection have some sort of check in it as to not let fuel flow backwards?

 

[Vivii]

Pull the flywheel. Key is in a slot in the shaft. See if it's there and undamaged.

When I pull the flywheel, do I have to do anything special as to not mess up the timing?

 

[oldboat1]

O-ring in the female clip will be tighter than the old clip. Also possible it's not a connector for OMC engines. The tank side of the connection has the check valve -- spring and bearing assembly.

 

[oldboat1]

When I pull the flywheel, do I have to do anything special as to not mess up the timing?

No. Clean the shaft with acetone or lacquer thinner when reassembling and torque to spec. Probably 105 ft lbs. Pull with a harmonic balancer/steering wheel puller.

 

[Vivii]

O-ring in the female clip will be tighter than the old clip. Also possible it's not a connector for OMC engines. The tank side of the connection has the check valve -- spring and bearing assembly.

I will try to get to it this weekend. If it is damaged or missing could it cause it to lose power?

O-ring in the female clip will be tighter than the old clip. Also possible it's not a connector for OMC engines. The tank side of the connection has the check valve -- spring and bearing assembly.

So you are saying it shouldn't be a problem?

 

[oldboat1]

Work it on and off, maybe with a bit of 2-cycle lube, to try and get the fit right. Should be square with the clip snapping in place. Everything is on the inside, including the O-ring.

 

[Vivii]

It has been a while since I have posted. I brought my boat to a local shop and they had it for almost 5 weeks and supposedly "fixed the timing" and did a new set of spark plugs, that were brand new before it went in. I was told that everything checked out good including spark and compression but there was some "noises" and it was the best it was going to run and start looking for a new motor. I put it in the water and sure enough, worse than before. After some slight tweaking, i figured out that providing a little more airflow into the cowl helped it to run better. Also if I detach the spark advance it will start and idle good and run up to approx 50% throttle. If I reconnect it, it dies again after shifting into gear.

Every tinenyou start it after it sits it needs to be choked for split second and then its fine.

Does this sound like my timing could be off? I have a feeling the only thing the shop did was adjust the spark advance forward stopper.

 

[ct1762@gmail.com]

I'd say don't take it back to those guys again! If they don't know how to do proper DVA ignition testing, they will be just guessing and costing you $. Sounds like an ignition issue to me. Could be the power or sensor coil, or one or 2 coils shorting out but since they didn't do a tests for ignition components, i'd buy an inexpensive DVA adaptor off ebay, a digital multi-meter for $10, and the factory service manual to run you though the tests. You will find out quite quickly if anything is faulty and/or going to ground. can you post a few pics of the powerhead... coils, and linkages especially cam roller?

 

[Vivii]

I'd say don't take it back to those guys again! If they don't know how to do proper DVA ignition testing, they will be just guessing and costing you $. Sounds like an ignition issue to me. Could be the power or sensor coil, or one or 2 coils shorting out but since they didn't do a tests for ignition components, i'd buy an inexpensive DVA adaptor off ebay, a digital multi-meter for $10, and the factory service manual to run you though the tests. You will find out quite quickly if anything is faulty and/or going to ground. can you post a few pics of the powerhead... coils, and linkages especially cam roller?

I don't plan on going back there, their communication was terrible and seemed to just want to get me out of there in the end. Was originally told 2-3 weeks worst case that turned into 4 1/2 weeks and several phone calls on my part to check in.

Here are a couple photos of the linkages/coils that I have on my phone. If you need a more specific one I can get it tonight. I have done next to everything that I can think of besides anything with timing or ignition system with the exception of changing plugs and testing spark for jumping a 7/16" gap.

I have a multi-meter along with the factory manual and could order a DVA adapter and give it a go following the book. The electrical system is the only system that scares me with wrecking something as I have ever played with/adjusted one before.

 

[racerone]

Strange that the " throttle safety switch " ( white switch ) has 2 wires going to it.----It only needs one , yes one wire to do its job !!----The switch is there now but not working as designed.-----Might as well throw the switch on the floor and hook the white wire to ground.----When I see that I immediately think, " what else is wrong with the wiring "

 

[F_R]

The red wire on the safety switch is in fact, connected to ground---same thing as grounding the white wire. In other words, the safety switch is defeated.