Yamaha 175 Lower Unit Questions

[Mikecoh]

Just bought a Grady White with a 1984 175 Yamaha. The boat has not been used in a year and I noticed that there is a little bit of oily residue on the bottom of the skeg as if it is leaking from the propeller shaft.<br />Should I assume this is lower-unit fluid?<br />Is this normal to see some very light seepage or should I assume that there are gaskets in there that are dried out?<br />If so, how hard a job is it to replace them and where could I find directions how to do it?<br />I'm hoping to get the boat in the water for Saturday but I'd hate to ruin the lower unit.

 

[rodbolt]

Re: Yamaha 175 Lower Unit Questions

change the gear oil and you will know for sure. if the motor will not turn its full rpm throttle back and idle back to the ramp. if the carbs are clogged partially and you try to "blow it out" you will most likly blow it up.

 

[Osprey]

Re: Yamaha 175 Lower Unit Questions

This can also be unburned 2-stroke oil. Which can be caused by the engine running to cool due to one or more thermostats being stuck in the open position. Once the engine sits for a few days the blackened oil drips out of the lower unit. Unless you are sure about the maintenance history, you should go through the cooling system anyway replacing the impeller, thermostats and service the poppit valve.

 

[Mikecoh]

Re: Yamaha 175 Lower Unit Questions

Osprey-<br />Thanks for that insightful reply. I think you may be right. When I picked up the boat one thermostat was junk so we removed it to test run the engine. It was run for a few minutes without the thermostat. I put new ones in today.<br /><br />Second question:<br />The motor will only start up with starting fluid, even when it's already warm. What is this usually a symptom of?

 

[easygo0]

Re: Yamaha 175 Lower Unit Questions

Is your choke working ,Is gas as old as boats been sitting .

 

[Triton II]

Re: Yamaha 175 Lower Unit Questions

Have you changed the plugs, 2-stroke oil and fuel? That'd be a good place to start. Also a carb rebuild would be an idea if things don't improve. Rodbolt or similar techs will be able to add much more!

 

[Osprey]

Re: Yamaha 175 Lower Unit Questions

I agree with above posts. If it was my engine, in addition to the cooling sys service, I would do the following:<br /><br />1. Dump and wash out both 2-stroke oil tanks and replace the inline filter on the external tank.<br /><br />2. Replace fuel pumps, cheap insurance.<br /><br />3. Replace water/fuel external filter. Clean fuel screen on side of engine.<br /><br />4. Do a de-carbon treatment.<br /><br />5. Replace plugs<br /><br />6. Confirm that carb butterflies are closing when choked.<br /><br />7. If still hard to start, remove, soak and rebuild carbs. Its likely time for this anyway.