115 yamha on a 20'

[Maxum21]

we'll ive finally found a nice used boat i really like. the price is right and i have my money ready to go. The boat is a 20' excel bowrider. The engine is a '93 Yam 115 v-4. Is there anything specific i should look for on this motor. I will be able to hear it run on muffs but i doubt a water test will be possible with this very cold weather..the only ob i've owned before this was a 93 force 90hp..many issues. i'm hoping i have better luck with a Yamaha...Also, do you think a 115 is sufficient for a 20' openbow? boat weighs around 2,000lbs.. probably going on thur for the boat. i appreciate any last minute opinions!

 

[ezmobee]

Re: 115 yamha on a 20'

I think a 115 is just barely adequate for a 20' glass boat. I'm assuming this is a Welcraft Excel. Welcraft makes fantasic boats, however I believe the Excel is their lower-end line. I have heard of them having rot issues (as is certainly possible with any older fiberglass boat) so you will want to check very carefully for that. You want a solid transom and deck. ANY soft spots in the deck can be indicative of more serious issues below.

 

[Bob_VT]

Re: 115 yamha on a 20'

Compression test..... all 4 cylinders

Ask about impellar?

Check lower unit oil for being milky.

Tilt and trim? Test it for full range of motion.

Look close at the wires and hoses..... look for cracking and weathering.

The 115 will probably be a fine motor for a 20' bowrider. Don't expect a speed demon but it should be fine for a skier or fishing.

Salt water motor? Look for corrosion.

How was the boat stored? Check for soft spots in the deck.... look at the transom and flex test it. With the motor tilted up and locked..... press down on the prop and also lift it..... does the transom flex?

Bring alone a second set of eyes too. Check the bilge pump, lights horn etc..... I would not take the owner's word .... I would check myself.

 

[rodbolt]

Re: 115 yamha on a 20'

if this is a salt water motor,look for the maint records. water pump,thermostats and pressure control valve should have been replaced in the past 2 years.
carefully inspect the shift shaft ,you can see part of it at the gap between the midsection and the steering swivel tube.
before 1995 that shaft was plain steel and did not hold up well in saltwater and usually corrosion makes it costly to replace.
if the above items have not been done in the past two years you will need to do them before using the rig but expect broken bolts.
you will also want to do a compression test,leak down test would be even better,trust me on this.
also be aware that most boats for sale sit, then when they attempt the seatrial they find the carbs need cleaning,fuel pump replacement is reccomended about every 3 years anyway.
personnaly,unless there was a warrenty, I would never buy an outboard without a complete in water seatrial.

 

[Maxum21]

Re: 115 yamha on a 20'

thanks guys for the advice..very helpful

i'm going to bring along a compression tester.. what would an ideal psi reading be for these cylinders? how much psi would indicate a needed rebuild? would milky oil mean bad lower unit seals? if i slide the prop/shaft back and forth, how much play should there be?

 

[ezmobee]

Re: 115 yamha on a 20'

Your biggest concern with compression is that the numbers are within 10% of each other. The actual numbers are often inaccurate on the gauge but will be at least be useful for comparison between cylinders. Milky oil would indicate bad seals. I don't know about the last question.

 

[rodbolt]

Re: 115 yamha on a 20'

no spec for propshaft endplay on that motor.
its either correct or the thrust washer got left out.
no shimming for prop shaft end play on that unit.