How fast should my boat run with 1985 Evinrude 150hp

[Monarkmcfast172]

I have a 1985 Evinrude 150xp on a 1986 Monark McFast 172 Fish/Ski. I am not getting a very good hole shot and I was just wondering if its because the weight and hull design of my boat. Top speed is only about 35 trimmed out and that just doenst seem right. I had a Nitro Z-8 with a 150 on it and it would fly around 75+mph. I just dont know enough about this Monark and want to make sure I dont have an engine problem. Thank you

 

[Bob_VT]

Re: How fast should my boat run with 1985 Evinrude 150hp

You need to diagnose the motor. What rpms are you turning at wide open throttle? There could be dozens of variables ......motor running right?......set up on boat......is your boat possibly full of wet flotation???

 

[Monarkmcfast172]

Re: How fast should my boat run with 1985 Evinrude 150hp

My tack isn't working right now but if I were to gues probably about 3000-3500 rpm's at WOT. And you mention the boat being full of wet floatation too. Hmmm. you got me thinking now about that too and from the sounds of it, that would NOT be an easy fix lol. I am going to wok on the tack today and try and get it working again and see what I can come up with. But I am also wondering if I am only running on two of the three carbs.

 

[dazk14]

Re: How fast should my boat run with 1985 Evinrude 150hp

It would be wise to get to the bottom of problem. That motor would push a 23' Walkaround 35mph.

If you run that motor lean, you can quickly put holes in pistons.

Is this a new to you boat?

 

[Monarkmcfast172]

Re: How fast should my boat run with 1985 Evinrude 150hp

Yeah I just got it about a month ago and have had it out 3 or 4 times. I am about to put new plugs in it and new wires and I have a feeling those wires were posing a big problem. THere is not much left of them inside the boots. All the cylinders have 90psi of compression right on the money so thats at least a good thing. I am going to tear into the carbs in a few minutes and give them a good cleaning. HOPEFULLY doing all this will cure this motor.

 

[5150abf]

Re: How fast should my boat run with 1985 Evinrude 150hp

Make sure you use a stranded copper wire to clean the jets, just pull abck strands till it just fits, also in all the passages and some sea foam helps.

Also if you don't have a cmpressor to blow it out the air in a can works really well and when you are done get an inline folter on it, even a cheapy plastic one is good enough, I put one on my boat 2 years ago and haven't had a carb problem yet.