68 evinrude 55hp

[jdt]

I have a 68 evinrude 55 hp. It runs great at low speeds up to 18-22 miles/hr.
When I throttle the speed up it bogs down and doesn't go. I then have to back down the throttle and it will resume speeds upt 18-22 miles/hr. Any thoughts? The butterflys open wide up and its like it starves for fuel.

 

[tashasdaddy]

Re: 68 evinrude 55hp

dirty carbs.

 

[jdt]

Re: 68 evinrude 55hp

dirty carbs.

The carbs were tore apart and cleaned and reassembled. They weren't that dirty at all. Any other thoughts? It is just agravateing because it runs good at low speed and I want to go fishing!

 

[rodknocker]

Re: 68 evinrude 55hp

Have you been copying my inputs??? HA HA HA. I have the same thing on my 65hp evinrude.

 

[F_R]

Re: 68 evinrude 55hp

Did you really look at the high speed orfice plugs in the carbs? I mean, really look? The least little bit of coating in the orfice hole will cause your problem.

You can remove and inspect the orfices without removing the carbs. You need a special screwdriver to get them out but you can make your own from a screwdriver with a 3/16" shank by cutting off the end and filing a new end on it.
http://i155.photobucket.com/albums/s311/frankr_photos/FixedJetScrewdriver2.jpg?t=1178993542

 

[jdt]

Re: 68 evinrude 55hp

High speed orfice plugs? Can you be a little more specific? I am new to the world of boat motors and carbs. I hate carbs! I was looking at the parts diagrams and I can't find it listed on the evinrude website under literature 1968 55hp evinrude 55873R 1968. If you could look and tell me wich number they are on the parts page then I would have a better idea about it.
I appreciate any ideas and thats one I haven't heard yet.

 

[F_R]

Re: 68 evinrude 55hp

Well, if you have the same edition of the parts book that I have, they are item #35, part number 314819 They are in the very bottom of the float bowl, down deep in the hole behind the hex headed plug. One in each carburetor.

Being in that location, they are right where the last few drops of fuel lay and turn to gum. As I said, they must be absolutely clean, not even a trace of gum. The hole or orfice through them is precision sized to regulate the flow of fuel. Don't tamper with the hole, just make sure it is clean.

 

[jdt]

Re: 68 evinrude 55hp

Ok. Thanks for clearing that up for me. I was looking at the diagram and that was what I thought you were talking about but I didn't know that was high spead orfice plug.. So I should take out the screw plug and washer and check to see if that orfice plug is clear? Maybe soak it or spray in some brake clean?
I thought that was just a plug to drain the gas out of the bowl. I will reinterate how much I don't know about this and ask a few stupid questions........Is that orfice plug plastic? How does that high speed orfice plug work with the carb? doesn't #36 pn 307832 SCREW PLUG on the diagram screw into it?

 

[Texasmark]

Re: 68 evinrude 55hp

No on the brake clean. Get some Berryman's Chem Tool for that job (any auto parts store, red-white-blue decals); spray or can. Made specifically for dissolving varnish in carbs.....brake clean is not. Spray it or pour it in and let it sit for a day or so. Blowing out with compressed air is one way to finish the job.
-------------------

Got yourself one of the revolutionary (started the looper revolution) TRIUMPH's huh? Great.

Mark

 

[Think oar Thwim]

Re: 68 evinrude 55hp

I too have a 68 Evinrude ,a triumph 55hp 3 cylinder,due to the sensitivity of the relationship between the electronics,and the 3 carbs on this model, it would be a great help to inspect the spark plugs to see if you have obvious signs of one or the other,either starved for fuel or flooding,as one or the other would indicate either too much fuel for the spark or vice versa,and could lead to something as simple as cleaning or re-gapping the plugs,or cleaning out the fuel filter.

I have had similar symptoms at different times where both were needed to fix,but the last time,it was as simple as re-adjusting the throtle lever spark advance.

There are far more qualified than I to assist you in this forum,but I thought I would at least add these personal experinces as it related to the same symptoms in my motor......Good Luck.........T.o.T.

 

[jdt]

Re: 68 evinrude 55hp

Understand NO brake clean. Thats good to know. I will pick up some Berrymans chem tool at Napa. I was going to bring in the old fuel lines and get new ones anyway since it is apart.
Triumph, yeah except it hasn't been tiumphant since I have owned it! I am really hoping this is the fix. I know they are good strong reliable motors but it hasn't shown me yet.......
Thanks,
jdt

 

[DHPMARINE]

Re: 68 evinrude 55hp

You might also look at that vertical arm that moves forward as you increase the throttle.It is spring loaded,and some times the timing part is gummed up,causing the throttle to advance faster than the timing.

DHP

 

[jdt]

Re: 68 evinrude 55hp

Is that on the drivers side of the motor?

 

[DHPMARINE]

Re: 68 evinrude 55hp

Yep ! Starboard.

Quick test.With the motor off,move the throttle forward quickly.If the timing part of the arm moves slower than the main arm,old grease is slowing it down.

DHP

 

[jdt]

Re: 68 evinrude 55hp

I will check that also when I get home. Sounds simple enought if I can figure out wich part is wich.
thanks
jdt

 

[F_R]

Re: 68 evinrude 55hp

BAcking up to the questions about the orfice plugs. No they are not plastic, but soft brass. No the hex plug does not screw into it. The orfice is deep in the hole behind the hex plug.

How does it work? It has a precision sized hole in it to meter the fuel flow. All the fuel has to pass through it. If it were too big a hole, too much fuel would flow, causing a rich running motor. If it were too small a hole, too little flow would flow, causing a lean running motor "Not getting enough gas, bogging, won't run at high speed" or however you want to describe it.

Gum, dirt or other contaminates in effect make the hole too small, restricting the fuel flow, causing a lean condition and all the usual complaints. It MUST be very clean!!! Can't say it any clearer.

 

[hightech]

Re: 68 evinrude 55hp

My 1971 Evinrude 60hp did the samething last year. It would run good when the fuel line bulb was being pumped or run slow for a little time, than would run good at WOT for a short time. I fixed it with a new gas cap! A cheap and easy fix. It took me all summer to find this fix. Like you I done everything esle before a new gas cap?

 

[jdt]

Re: 68 evinrude 55hp

Ok. I took the carbs back off and removed the bowls. Removed the hex bolt on the bowl and checked all three High speed orfices. They all looked the same. I could defenitly see how they could get clogged. But they looked pretty clean. I bought some berrymans chem tool and new fuel lines so I decided I might as well soak them. I soaked the bowls overnight. Today I looked at them and blew them out with some air. I put them together and reinstalled them on the boat. Tomarrow I will finish putting the fuel lines on and the air cover. With any luck on saturday I can drop it in the water and see if the problem is still there. In the first carborator there was 2 very small things of grime. I don't know if one carb high speed orfice is clogged if that would effect the high speed enough or not. But we will give it a try. I am also going to buy a new gas 6 gal gas tank and cap and see if that might be it. I have tried a new primer bulb line and that didn't help so I think I can cross that off my list. Any other thoughts?

I appreciate all of your ideas and help with my stuborn old motor.

 

[jdt]

Re: 68 evinrude 55hp

Could the fuel pump cause this problem? Could it work fine for slower speed but not for faster speeds above 20mph? I was trying to test the fuel pump and my manuel says that to disconect the fuel line from the fuel pump to the carb and crank the motor 15 pulses and check how much fuel comes out. I did that and I get fuel coming out but how much should come out to show a good fuel pump?
Any thoughts please?
jdt

 

[F_R]

Re: 68 evinrude 55hp

A better test is to use a pressure gage while running. A simpler test is to simply squeeze the primer bulb and see if that makes it pick up. In squeezing the bulb, you are doing what the fuel pump does for you.