70 hp Evinrude wont run wide open

[scot2hot]

I have a 1974 70hp evinrude,idles great but when i put in gear it just bogs down if i put it in nuetral and rev throttle in revs up,but not in gear.please help

 

[Big Bubba]

Re: 70 hp Evinrude wont run wide open

How old is the fuel/gas in her. If you don't know how old the gas is and it is stale it will run like that for sure. I learned that the hard way with my first speed boat but luckily my dad was there and knows about boats and now I am picking it up myself. Basically we got rid of all of that bad gas and put fresh oil/fuel mixture in it and it ran GREAT!!!!! after that. You also might need to rebuild your carbs if that doesn't solve the issue by getting rid of old gas and putting fresh gas oil mixture back in her. Let us know, Bob

 

[lostinboat]

Re: 70 hp Evinrude wont run wide open

I have a 87 70hp, Mine would run great until I put it into gear and then would just bog down . out of gear it would rev right right and run great, found out I was losing spark under load. try using a spark tester when under load.My prolem turned out to be a bad power pack. replaced it and my no more trouble.hope this helps.

 

[Jeff_G]

Re: 70 hp Evinrude wont run wide open

Could be any number of things.
Fuel, either old fuel, carbs gummed up from sitting, worn fuel pump, or even a ruptured fuel pump diaphragm.
Ignition, bad coil, fouled spark plugs, defective trigger or power pack.
If you have a timing light hook it to #1 cylinder run the engine in the water, in gear, NOT on a hose. Check for even flashing from the light. Do the same for the other cylinders. If you have a bad cylinder try changing the coils with another, if the problem moves the coil is the problem. If it stays on that cylinder it will be the trigger or power pack. The only way to definitively check is with a DVM peak reading volt meter.

Very important NEVER rev your engine in neutral or out of the water, it MUST have a load on it.

 

[SparkieBoat]

Re: 70 hp Evinrude wont run wide open

get a spark tester from auto parts store..first thing to check. should be a blue streak with a 1/2" gap