70 HP Evinrude problems :(

[cowboy67]

I have a 1974 70 HP Evinrude motor. 1st boat too. Was so happy to get it until I got stranded in the middle of the lake W/family. Any way, The motor sat for awhile and I have changed the gas. The problem I have, is when I go full throttle, it is really sluggish and then will finally open up. When it runs at full throttle if i were to turn, the motor will act as if I were throttling down. I believe the float in the carb may be the problem but looking for verification. Also, there is a fuse that keeps blowing in the motor. Anyone know what this fuse is for and why it would keep blowing? Any help would be greatly appreciated!

 

[JB]

Re: 70 HP Evinrude problems

Howdy, Cowboy. You have three carbs on that engine. What you describe could be one carb lagging in providing fuel due to a low float setting or gummed up jet. Recommend cleaning and synchronizing all three. It is also possible that your fuel pump is marginal in supplying enough fuel.<br /><br />The fuse protects your battery and charging system from short circuits. Sounds like you have an intermittent short somewhere in your ignition switch or accessories circuits. My book doesn't say what size it should be, but they are typically 20 amp. Make sure that it is the right size (check with your local OMC dealer). If it is correct, you need to troubleshoot you electrics and wiring to see where you have a bare wire touching what it shouldn't.<br /><br />Good luck.<br />JB

 

[cowboy67]

Re: 70 HP Evinrude problems

Thank you Sir! I will check those possibilities. When you say synchronize the carbs what do you mean by that?<br /><br />Anyway, Thanks again!

 

[JB]

Re: 70 HP Evinrude problems

Synchronizing is adjusting the linkage between the carbs so that each has the same amount of throttle at the same time.<br /><br />Luck.<br />JB

 

[foosballpaul]

Re: 70 HP Evinrude problems

I have a 1975 70 HP Johnson that had similar problems. Replacing the needle valves and seats on all three carbs corrected problem. You should be able to get the needle valve kits from local OMC dealer for under $5.00 each and they are realitively easy to change. If the center carb is the one giving you problems it will affect the other two. The center carb has a fuel tee which feeds the upper and lower carbs. In my opinion, those old mid seventies three cylinder Johnsons were almost bullet proof if you keep them tuned correctly.

 

[scottsabre]

Re: 70 HP Evinrude problems

I tried to get just the needle/seat repair kit so I could put my carbs back together, (found nothing wrong with them)but store told me I could only get the rebuild kit, $13 ea. X 3. What does the kit your talking about give you?

 

[foosballpaul]

Re: 70 HP Evinrude problems

The older needle valves had a fiber tip and over time would develop a small groove/deformity that is barely visible. The ones that came in the kits I purchased did not have the fiber tips. The kits I bought contained the needle valve, seat, and retainer spring. I am in Maryland and I just purchased the kits for $3.75 each. Don't know what part of the country you are buying your parts but I'm glad I don't have to do my shopping there.

 

[kalloway]

Re: 70 HP Evinrude problems

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[MooseMan]

Re: 70 HP Evinrude problems

I am assuming that you bought this boat used - if you did so was it from a dealer or an individual. Either way it might be worth determining when the last time the carbs were tuned up. If it has been a long time - get the carb rebuild kits and start from scratch to avoid a hasstle down the line. Then have them properly sync'd and linked - a timing light will be required. Finally if your spark plugs have not been replaced in the last year, you should do those as well. This might seem like overkill but if it hasn't been done in a long time it may definitely be a contributor to the problem.<br /><br />Let me ask one other question - you said that when you turn it sputters out on you - is it when you turn in either direction or just one direction. Also does this just happen at full speed or at all speeds? I am curious about your blowing fuse and was wondering if the turning action was causing a wire that the insulation has been stripped back to ground out - blowing the fuse and affecting performace at the same time?

 

[Torpedo]

Re: 70 HP Evinrude problems

Check your coil & wires as well. The wires tend to get loose and the old coils maybe grounding our for some reason...