t-stat on a 57 18hp fastwin

[Wizard1]

I have a 57 fastwin 18hp (15020-19224) that ran a little hotter than I liked last year. I am going over everything I will need to put it into the water this season for fishing and I need to know if anyone can tell me where the t-stat is exactly? If you were standing in the boat looking at the motor, there is a plate on the right hand side behind the fuel bowl. Is it behind that plate or is it on top of the head? The plate that I am talking about has a rounded section at the top with a bolt at either side which is why I think it is there. But I am not sure and I do not want to start pulling things off this motor randomly looking for it.<br />Also, is there a website I can goto to see a diagrom of this motor?<br />Thanks

 

[Chinewalker]

Re: t-stat on a 57 18hp fastwin

Hi Wizard,<br /> There is no thermostat on a '57 18. Didn't come into the 18s until 1959 model year. The plate you are referring to is the exhaust cover plate. <br /><br /> Have you replaced the water pump impeller? Checked for good flow through the powerhead? If it comes down to it, you may have to pull that exhaust cover to check for blockages, particularly if the old impeller lost bits of blade.<br /><br />- Scott

 

[Paul Moir]

Re: t-stat on a 57 18hp fastwin

You'll be looking a long time. The 18hp didn't get a thermostat until 1959. If your block or head has been replaced with the one that does have a thermostat, you'll find it underneath a plate in the top of the head. The plate is easy to spot, being held on by three screws or bolts.<br /><br />I don't know of any online diagrams covering the '57. I don't see any in my collection.<br /><br />You need to have a long look at the water pump. If the housing or wear plate is worn, that's likely your problem.<br /><br />EDIT: Too slow..

 

[Wizard1]

Re: t-stat on a 57 18hp fastwin

Thanks guys, I guess I won't look for it then. I replaced the water pump impeller at the end of the fall last year and it was missing a few small parts. The housing looked in great shap so I left it alone. After I replaced the impeller I did not take it back to the lake I fish most of the time (lake conway) and I didn't ru it very much so I'll check it out this year. I think I will pull the exaust cover though, just to make sure.<br /> Now I have another question. I have pulled the flywheel due to a problem I found the other day while going over the motor. The spark plug wires have small cracks in them up under the timing plate. Is is itpossible to replace the plug wires without pulling the entire timing assemblly apart? I have been told that the plug wire can be replaced without replacing the coil but I am not sure.<br />Thanks

 

[Chinewalker]

Re: t-stat on a 57 18hp fastwin

Hi Wizard,<br /> It's actually much easier to replace the wire if you have the coil free of the armature plate. Not to say it can't be done with the coil in place, but you'll use far fewer colorful words doing it the "long way". In the end you'll be done quicker and are less likely to accidently break something or bend over the spike in the coil that makes contact with the core of the wire. If you've had the flywheel off, you're halfway home already. You don't even need too completely remove the coil - you can remove the mounting screws and leave the primary wires in place...<br />- Scott

 

[Wizard1]

Re: t-stat on a 57 18hp fastwin

Thanks again, I'll remove the armature plate so I can keep my sanity. Oh , do I need to get a certain type of wire or can I use any quality plug wire to build them?

 

[Paul Moir]

Re: t-stat on a 57 18hp fastwin

You absolutely must use spark plug wire with a metal core. Which is unlike any automotive spark plug wire used since the 60s. Car spark plug wire is resistive to help with RFI, but it often causes mid-throttle misfires with these old magnetos.<br /><br />It also must be 7mm OD wire to fit the ignition coils properly. You can get this stuff from any mower/small engine, or marine shop as well as some of the better auto supply places. The marine guys charge me around $3/ft for it, but you can get it for half that if you shop. You'll need 4 or 5'.

 

[Wizard1]

Re: t-stat on a 57 18hp fastwin

Thanks, I hope to be in the water as soon as it gets a little warmer here. Crappie season is coming up soon.