'98 Yamaha 115 - New Owner - What should I do first?

[BOAH]

I just purchased a '98 115. I would like to go through it and replace the maintenance stuff on it. Thermostat, fuel lines, impeller, etc. Is there a file available detailing all of the things I should go through?

Thanks for your help!

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

bump....

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

I took out the thermostats last night and found both of them in bad shape.



No way could they have fully closed. I cleaned / vacuumed what I could out of the head. I then replaced them. I've got an additional water flushing connection at the bottom of the cowling. Will that help to remove some of the stuff I found under the thermostats?

I see there is an additional water pressure valve at the bottom of the motor. Is this also called a poppet valve? I've seen references to this elsewhere. Should this be replaced or can it just be cleaned out?

Thanks for your help.

 

[99yam40]

Re: '98 Yamaha 115 - New Owner - What should I do first?

depends on what it looks like, but I would replace with new. Make sure you clean build up out from under grommet as that will cause sticking of valve also.
Make sure you do not lose it inside motor

Owners manual should give info on what to do and when

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

Thanks, 99yam40. The only thing that I have found on it so far in the manual is to check / replace this pressure valve if you're having circulation / overheating problems and the water pump and thermostats are in good working order. I'm just doing preventative at this point.

Thanks

 

[99yam40]

Re: '98 Yamaha 115 - New Owner - What should I do first?

it is listed as Once a year inspect/replace as needed

If you do not know if it has ever been inspected or replaced it would be a good idea to do it before it causes you to lose a trip because of motor problems. They did come out with a different design on the valve at one point to help with sticking problems, but I have no idea what year

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

Is it a trick to get the seat out that the valve sits on or does it typically come out pretty easy? And on reassembly, the manual says that no sealant or adhesives are required. Does that apply to the bolt threads or do you normally put something on the threads?

Thanks again

 

[99yam40]

Re: '98 Yamaha 115 - New Owner - What should I do first?

I believe it is just a rubber grommet

a little grease on bolts makes them easier to come out next time, but that is just my opinion

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

Thanks, 99yam40

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

99yam40, I was able to replace the grommet but now I see what you mean about not losing that inside the motor! That would have been an easy thing to do.

Thanks again!

 

[Bamaman1]

Re: '98 Yamaha 115 - New Owner - What should I do first?

The older Yamaha 2 stroke motors are really reliable, however the modern 90/10 gasoline has a tendency to gum up carbs and affect anything rubber in the fuel system. Regular maintenance items are:

Clean and re-grease the trailer bearings--step #1.
Put the boat into the water, get the engine warm and put the boat back on the trailer.
Drain the lower unit into a clean drain pan--looking for water intrusion.
Drop the lower unit and change the water pump impeller.
Replace the lower unit grease.
Change spark plugs.
Change the fuel filter element beneath the carbs.
Replace the rubber membrane in the fuel pump (also under the carbs.)
Check out all the fuel lines, the bulb and the siphon tube into the fuel tank.
When your engine starts for the first time, is it putting out blue smoke? That'll tell you if the engine's getting oil.
If your engine does any stumbling at all, pull the carbs. and clean them. If you're careful with the gaskets, no carb kit is required. Just keep track on how many turns of any adjustment screws were required to seat them, and reset the screws to where they were before.
Don't hesitate to have a marine mechanic do a pressure and vacuum test on your lower unit to test the seals. It's a $300 repair if bad.

Fortunately, these repairs are not very expensive if you provide the labor. And few tasks require much mechanical skills, either.

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

Thanks, Bamaman1. So far, I've replaced both thermostats, replaced the pressure valve, cleaned the fuel filter, replaced the fuel line going to the tanks, replaced all of the oil in both the external and motor-mounted oil tanks, replaced the impeller and installed a new water pump kit and pulled off and cleaned the prop and shaft and lastly checked to make sure my overheat buzzer works.

I then fired it up with pre-mixed 50:1 and idled it for 30+ minutes while flushing it with the salt off flush kit. I took a quick look at the lower end oil and it looked good so I'm going to run it in the lake tomorrow and then change the lower unit oil when I get back and see what it looks like then.

Before I go tomorrow, I'm going to run it again in the driveway with regular gas just to make sure.

Thanks for your help and input.

 

[BOAH]

Re: '98 Yamaha 115 - New Owner - What should I do first?

I also replaced the the throttle and the shift cable, the oil-level sensor and the prop. I ran salt-off through the motor and I'll probably do the vinegar trick as well to try and clean it out as well as I can. I ran it in the lake a couple of more times and then we left on our trip. We were gone for a week of boating and the motor ran great all week. Thanks again for your help!