150 evinrude on 18 ft neptune

[spicerak]

hey couple of questions my mecanic put a manual thing on for my engine to go up and down but it works fine but when i turn some times the idle goes up like it is cavating what height should it be also how fast do u think i should go in thaqt boat on my gps it says about 30 is that about write at 4200 rpm.also its hard for me to get to 5000 rpm only way is tilt engine up but it would cavatate

 

[tashasdaddy]

Re: 150 evinrude on 18 ft neptune

you either have a sick motor, or need to reprop to get more rpms. what year and model # is it. have you check the spark and compression on all cylinders.

 

[spicerak]

Re: 150 evinrude on 18 ft neptune

it is a 150xp 1989 compression 90 all around 21 prop im scared to go smaller to blow engine what rpm should i run it at.also when i check the plugs on one side they dont look moist with oil is that a problem thanks alot for the help.the other side looks good how fast should i go this is with a gps speed