1974 evinrude 135 engine trouble

[fishingman]

I just got a 1974 evinrude 135 starflight motor. Its on a 81 ranger 350 18 foot fiberglass boat. When just idling it gets up to about 5000 RPMS (approximately because i dont think the Tach guage is accurate). When i took it out in the water and put it at full throttle, I am only getting aroung 2000 RPMs at full throttle. The throttle cables are good because they are moving the parts on the motor to the fully open positions. I rode it around a while at full throttle to see if the carbs are gunked up but no change. It runs very smooth, no shaking, sputtering or anything. It just seems like something isnt kicking in to power it up. I read some other threads and i hear about the boats getting stuck in SLOW. Do you think this could be the problem and if so how do i solve this problem. I dont have a manual for the motor so im lost. If you have any suggestions, i would love to hear them, please give instructions aas well if you have any ideas because im new to boats Thanks

 

[ezeke]

Re: 1974 evinrude 135 engine trouble

Your motor does not have S.L.O.W. or any other protective similar devices, So it is very important that it not be run over 1500 RPM unless there is a load on it.

The boat will have to get on plane before the engine will reach the higher RPM that it is capable of; that will require that you trim the motor properly, so try moving the thrust rod in and out on different runs until you can get on plane. If your propeller has too high a pitch, you may not be able to do it.

The horizontal plate above the propeller should be parallel to the water at WOT for best results, and it should be parallel with the bottom of the boat to start with.

 

[fishingman]

Re: 1974 evinrude 135 engine trouble

Thanks for the advise. The trim motor is not put on so I had it in only 1 position while in the water. DO you think it could be as simple as the trim. Its a 135 hp motor and the boat is only an 18 footer ranger 350. I would think it should still be able to hit the RPMS even if the trim isnt in the right spot. Im only getting about 2200 RPMs max.

 

[ezeke]

Re: 1974 evinrude 135 engine trouble

If the motor is too far in towards the transom at the bottom, it will lift the stern, forcing the bow down. If the motor is too far out at the bottom, it will push the stern down, forcing the bow up too high. In either case you may not be able to get on plane.

There are many other possible explanations why a good running motor can't reach WOT, these are easy to check.

 

[mrcj001]

Re: 1974 evinrude 135 engine trouble

It sounds like the boat isnt getting up on plane. With out a trim and tilt that maybe hard to do. I have a `75 Johnson 135 on a 16` and at first it would take a while to get it to plane and when it did it would porpus a lot.

Since you dont have the trim and tilt, try some smart tabs...they really helped my boat to plane faster and I dont have to fool with the T&T to much anymore.....

BTW....that 135 is a horse...it should push that boat to aleast 40 MPH

 

[ezeke]

Re: 1974 evinrude 135 engine trouble

Just try the thrust rod in different positions. The 1974 135 is about a 110 to 115 in todays rating system and it doesn't get to the then certified 135 until you are at 4800 RPM. It is plenty of motor if it is set up correctly but everything needs to be considered.

 

[fishingman]

Re: 1974 evinrude 135 engine trouble

thanks for all of your suggestions. I will try them out and let you know if any of them work.