'69 105hp cooling issues (thermostat/starter)

[Saltzman]

I recently purchased a project boat (my first)--a 1969 16' Chrysler Sport Fury with 105hp outboard. It had sat outside for at least the better part of a year since being in the water, however I was able to get it running by cleaning up the points/carbs. The first time we took it to the lake was somewhat of a bust--it idled around ok but as soon as we got past the no wake buoys and tried to rev it up it died (think probably points-related) and we ended up going back under trolling motor power. During the time it was running, I never got a heat indicator. It also cranked fine until we gave up and pulled it out of the water, and when we got it home.

After deciding to go ahead and buy the tune-up parts to fix everything up right, I started having starter problems. I pulled it off and took it to a local auto electrical shop--they said it had an open in the armature--probably due to getting hot enough (~450 degrees) to melt the solder out of the connections to the brush contacts. They fixed it all up and everything was peachy. I installed new points, carb kits, and water pump impeller, and took it back to the lake. The motor ran fine, but when idling around for 5-10 minutes the heat indicator would come on. Revving the engine up for a little bit would turn the indicator off and I wasn't overly concerned.

Fast forward to today--getting ready to take the boat back out with my girlfriend. I had the trailer all hooked up, gas mixed, cooler packed, and everything ready to go. Before we pulled out I hooked the battery up and tried the key--and got nothing. Suspecting the battery, I switched to the trolling motor battery but still didn't get cranking. Checked the solenoid next and everything seemed normal, so I pulled off the starter and it looks like the solder melted out of the armature connections again. What appeared to be a ball of solder fell out of the cap and there was also visible solder splatter on the brush wire insulation.

I don't think fixing the starter is a big deal, but what do I need to do to keep it from happening again? I put in a brand new water pump impeller, however I also discovered the engine doesn't have a thermostat installed. Would the lack of a thermostat cause it to run hotter at lower RPM conditions? I would think it would be more a case of running too cool, but that's not what I'm experiencing at all. Is there anything else I should look for?

Thanks for the assistance--I'm still pretty new to marine engines.

 

[Frank Acampora]

Re: '69 105hp cooling issues (thermostat/starter)

Those old 2 piece lower units had a much smaller impeller than the newer 1 piece lower units. Your impeller is about 3/4 inch thick. the newer ones are an inch or slightly more. Pumps and impellers can not be inter-changed. If the idle speed is too low, it is possible that it is not pumping enough water to cool. Here's why: At low speed the impeller vanes flex and pump water like a displacement pump. At high speeds, water pressure forces them away from the pump wall and they pump water like a centrifugal pump. That's why they dont wear out at high speeds.

Now: as for the starter: it is a very high amperage, high torque motor. A lot of power goes through it and it generates a lot of heat fairly quickly. Excessive cranking form a hard starting engine may cause it to overheat. You are only supposed to crang for a few seconds at a time then give it time to cool.

And, Believe it or not: if you have low voltage due to corrosion or high resistance connections it will cause the motor to draw even more amps heating up quicker.

A well tuned 105 will start fairly quickly by pull cord if you first prime it. Just don't have your girl standing behind you. That rope will snap her like a wet towel and she will never go out with you again.

 

[QuadManiac]

Re: '69 105hp cooling issues (thermostat/starter)

To re-solder the starter use a higher temperature solder like 30/70 (melts at 496 F) instead of 60/40 (the most common type, 375 F).

Even with 60/40, the solder joint shouldn't get hot enough to melt during engine running, even if the engine is overheating. The starter is likely heating itslelf up enough to melt the solder during starting. Higher temp solder should mitigate this problem. BUT, the temperatures are being generated by other issues like worn or improperly seated brushes, etc. Fix the underlying issue, use hi temp solder and hopefully you will never have to visit this one again.

Good Luck!

 

[eurolarva]

Re: '69 105hp cooling issues (thermostat/starter)

An aftermarket starter will run you around 150 dollars. Could be the solder was a cold solder joint and it just fell off. If you have a hot enough solder iron you could try a solder with a much higher melting point.
Solder click here

 

[QuadManiac]

Re: '69 105hp cooling issues (thermostat/starter)

And, Believe it or not: if you have low voltage due to corrosion or high resistance connections it will cause the motor to draw even more amps heating up quicker.

This actually can be true, but not in all cases. If the voltage at the starter (caused by high resistances in the current path to the starter due to corrosion) is low enough to cause the starter motor to run at or near stall, the current will be at its maximum.

 

[QuadManiac]

Re: '69 105hp cooling issues (thermostat/starter)

Hey, Euro... I wuz just looking at that page, lol.

I used to design and build high temperature electronics for systems that are lowered down into oil wells, where it can get above 200C (392F). I was trying to refresh my memory on what solder I used. It was 30/70 for those applications. A little harder to solder with, but you get used to it fast.

 

[Saltzman]

Re: '69 105hp cooling issues (thermostat/starter)

Thanks for the info guys... after exchanging a couple emails with Franz (Franz's Marine) I was starting to think the starter and low speed overheating problems were probably unrelated, as well.

Toward the end of our last outing we had some minor fuel issues--I made the mistake of getting ethanol blend gas, and the ethanol separated out after adding 2-cycle oil. We did have a little trouble getting it started around that time, so that may have been when we fried the starter. My hunch is that it melted out most of the solder while cranking so there wasn't much holding together (but enough it always cranked fine on the water), then fractured while bouncing down the road on the trailer bringing the boat home. Franz said he thought some starter shops could spot weld the armature connections rather than soldering them, but for the near term I think I'll try the 70/30 solder idea and try to take it easy on the cranking.

For the overheating Franz recommended a complete water pump kit, which I think contains a new housing/wear plate as well as impeller. When I replaced the impeller a couple weeks ago, though, the housing looked to be in pretty good shape. Is there anything else I should do or check that might be causing the problem before I shell out ~$80 for the pump kit?

 

[QuadManiac]

Re: '69 105hp cooling issues (thermostat/starter)

Since you just installed a new impeller, I would be looking for any possible obstrucitions to flow that would limit cooling and cause the overheat at idle.

Anybody know whether the temp warning switches ever move to lower temps as they degrade with age?? Just fishing here.

 

[Quint124]

I have a 1969 chrysler fury boat does anyone out there have one?

 

[jerryjerry05]

Welcome to Iboats.
The post you added to is 8 years old.'Maybe start a new one?
The forum is for repairs.Post something you need fixin and then ask if there are others out there?
Post a pic of the boat/ motor.
Back in 69 they were popular. I imagine most have been chopped up.