64 evinrude Starflite 90-s not full power

[bob.mag]

hello,
This is a really nice site you got. I was wondering about my 64 90s evinrude.... it will idle just fine but when you give it full gas it goes faster but not as it should, the boat does not plane out and its just pushing water. I was going across the lake like this last Sunday and all of a sudden the motor just revved up the boat planed out and it went like a bat outta hell.... I turned around and tried WOT once more and could not get it to do it again, all it would do was push water and bring the front end up high. I put brand new plugs in it, I did a compression check and got 105-110 on each cylinder, I looked and the timing marks line up perfectly on the flywheel and on the teeth of the distributor cap.... Any ideas on what the problem might be? I also drained the lower unit were the drain screw is for the oil and all that came out was about a quart of water

 

[bob.mag]

Re: 64 evinrude Starflite 90-s not full power

no input from anyone? anything would help....

 

[boobie]

Re: 64 evinrude Starflite 90-s not full power

You better reseal that lower unit first or you'll be junking the mtr. When the prob occurs, pull one spark plug wire off at a time and see if you can find out which cyl/cyl's are not firing.

 

[bob.mag]

Re: 64 evinrude Starflite 90-s not full power

OK... one more question I have is that it is leaking oil from a very small hole above right above the prop and sometimes another very small hole above the water inlet screen? these holes are definitely stock, and were would the thick black oil come from???

 

[tx1961whaler]

Re: 64 evinrude Starflite 90-s not full power

The thick black stuff is unburned fuel-oil mix. Perfectly normal.

 

[F_R]

Re: 64 evinrude Starflite 90-s not full power

Agreed, reseal that gearcase, before you destroy the gears, bearings, and electric shift. As for the performance problem, your motor is not running on all four cylinders. Except for that one time when the missing cylinders kicked in and it took off.

Replacing spark plugs was a wise first step, but since that didn't help, you have to figure out what else is wrong before fixing anything. That motor has four cylinders, four plugs and plug wires, a distributor with a rotor and two sets of breaker points and one condenser and coil. It also has a four barrel carburetor, each with separate floats and jets feeding each of the four cylinders.

While one section of the carburetor not feeding fuel is a real possibility, I would guess the problem is ignition---specifically one set of points. Each set of points fires two cylinders, so if one set is defective, you run on the other two cylinders---and may cut in and out as the bad set of points decides to make/break contact.

Carburetor parts or kits are obsolete, and very expensive if you do find them. For that reason, stay out of the carburetor unless you are darn sure there is a problem there.

Breaker points (18-5156), condenser (18-5199), or tune-up kit containing both (18-5001) are all available here at iboats.

 

[bob.mag]

Re: 64 evinrude Starflite 90-s not full power

OK, I will reseal up my gear case and then I'll try the point and condenser kit. Thank you for all your help,
I hope this works I will post up this weekend what the change was.