15 Ward hi speed op problem

[jakeyman_i_am]

Hello,
New to the forums - I purchased a 15 foot Toma fiberglass boat with a Montgomery Ward 15 on the back of it.. The previous owner said the motor runs great, and he is right except for one rather major issue - It seems to overheat when it is running full speed... It will idle and run slowly in gear forever, but when you open it up, it will run for about a minute before it starts steaming and soon it will bog like it is running out of gas (overheating?) and die.. It will start right back up 10 minutes later..

I first though it was choked for fuel so I tried a new line and a different tank.. No luck.. Checked the water pump and the impeller looks good, no obvious clogs in the water intake or tube running to the power head..

I'm wondering if maybe the fuel pump diaphram is worn, and causing the motor to go lean at hi speed, that would make it run hot wouldn't it?

Any ideas guys, I'm stumped! Thanks in advance and I hope to give back to the forums once I know what I am doing!

 

[steelespike]

Re: 15 Ward hi speed op problem

Welcome,
There are a number of MW 15hp. A model number would help or a picture.Or even a description and best guess of the year.
If it is over heating stop running it to the point of stalling.Shut it down as soon as you get any indication its hot.Any number of things can cause it.Not the fuel pump though. Impellers get stiff and can take set from sitting.The water tube may be leaking at the power head or pump.Any chance it has been run in salt water?
Could be corrosion in the passages. Normally there is a relief hole or outlet that water comes out of.See any water discharging?Seeing you have let it stall a couple of times it wouldn't hurt to pull the head and look around for scoring and blocked passages.