Bought a 1970 115HP Evinrude starflite

[HypnoCraft]

Hi, I recently bought a 1970 115hp starflite with electro-hydraulic shift. It also came with a 1973 125hp parts motor. The 115 had a leaky lower unit so I decided to swap them over. That worked out no problems encountered. I checked the water pump when I did the swap and all the legs of the pump were intact and maybe only 1/16" was worn from the sides of thee tips.

I put it all back together, put it in a bucket with the water just above the anti-cavitation plate and gave it a run. I know this motor doesnt have a tell-tale, so I let it idle for a min or so and touched each head. they were hot. so I turned the motor off and started wondering if I was getting water. Long story short I decided that the thermostat must be dead, so I took apart the thermostat box. What I found was the not only was the thermostat missing but so was the low pressure return poppet!

So, just as a sanity check... I ran water through both sides of the heads to make sure water could pass through them, and it did. I got a stream of water coming out of all the holes in the lower and the intake which makes sense because the low pressure poppet was still missing. So I put it all back together and took the spare poppet valve and thermostat from the parts motor. I checked the thermostat by placing it in boiling water and watched it move ~1/16 or an 1/8th of an inch.

Anyways, I was wondering, since the poppet and thermostat were missing, would that contribute to overheating? my thought process is that the water would continually circulate from the pump up through the heads, out to the low pressure poppet that missing and back down to the pump. I just wanted to ask here before I fire it up again. I realized now that I have an infrared thermometer as well. The operating temperature of the heads should be below 170f correct?

 

[racerone]

To test run in a bucket the water level MUST be 6 or 8 " above the impeller.----If impeller looked worn it needs a new one now.----A 1972 model 125 HP is what you have in 1973 it was 135 HP with a different shift system !

 

[HypnoCraft]

To test run in a bucket the water level MUST be 6 or 8 " above the impeller.----If impeller looked worn it needs a new one now.----A 1972 model 125 HP is what you have in 1973 it was 135 HP with a different shift system !

I am kind of confused about test running in a bucket with 6" above the impeller. When it's on a boat there's no way its 6" above. I guess moving at speed primes the pump? What if I test run it with muffs? Can I do that safely on an older motor? It's pretty hard to find a bucket large enough as well as tall enough to get 6 to 8" on the impeller.

Thanks you for the advice on the impeller. I will order a new one.

 

[racerone]

Water in your test bucket must be 6 or 8" above the impeller !----A fact for you to learn !

 

[oldboat1]

Either start it on muffs with the water at about half pressure, or test in a deep test barrel (trash can?) I try to have the water about half way up the leg, and leave the hose running. As I recall, my '70 85 Starflite had an electric gearcase and required Premium Blend lube (thin, like ATF). You need to replace the impeller.

 

[HypnoCraft]

Water in your test bucket must be 6 or 8" above the impeller !----A fact for you to learn !

Thanks, I will keep that in mind if I use a bucket again!

Either start it on muffs with the water at about half pressure, or test in a deep test barrel (trash can?) I try to have the water about half way up the leg, and leave the hose running. As I recall, my '70 85 Starflite had an electric gearcase and required Premium Blend lube (thin, like ATF). You need to replace the impeller.

Thanks! Started it on muffs and it spits water now! And yeah I used Type C gear oil which was specified by the manual. I will for sure be replacing the impeller very soon!