Yamaha - after 27 year nap...with VIDEOS

[77SceptreOB]

Recently I was having some performance issues cropping up with my old Yamaha 225 hp 2 stroke outboard. It is a 1988 and we bought it brand new 27 years ago. I thought it might be nearing the end of it's life due to old age problems. It was surging and hiccupping. The idle was getting pretty rough and the hole shot was getting pretty weak. The top end was okay at 38 mph but I could only now turn up 5100 rpms at WOT. Also the low speed performance was not all that good either with vibration and out of tune and song sound. I thought we were near the end and a very expensive 4 stroke upgrade was going to be in my future. I could make that happen from a financial perspective, but it would be a stretch and with college for my kids in the next 5 years I would really have to think long and hard about this...

I was talking to a mobile marine mechanic that works out of the marina I keep my boat at about these problems. He gave me a few suggestions to look into but he didn't want to work on such an old motor due to the time involved to trouble shoot everything and he was very busy. I was pretty discouraged. One point he made clear was to run a compression check on all 6 cylinders BEFORE I did anything or spent any money on parts. That made a lot of sense to me.

So armed with my friends compression gauge I went to the marina to run a compression test on all 6 cylinder to see what I had. Honestly, I wasn't sure what I would find and had serious doubts.

I warmed the motor up with a little ride on the lake. Motor was not running too good as mentioned above. I pulled into a covered wet slip and commenced to do the compression check.

The first cylinder was 125 psi. I thought that was excellent and my attitude went from near death motor thoughts to some optimism.

The # 2 cylinder was 126 psi, #3 was 125 psi, # 4 was 122 psi. I was pleased but guarded thinking the next cylinder would be 50 psi or something like that. BUT, #5 was 120 psi and the last cylinder....drum roll please....was....120 psi!! I was very happy with these readings needless to say!

Well buoyed by this good news I walked over to the marine mechanic to share my great news. He said that was surprising and actually pretty impressive for the age of the motor. BUT---He still declined to work on the motor. I left to go back to the boat with a deflated attitude.

I tinkered around on the motor but nothing really helped. New spark plugs etc... When leaving the marina the mechanic whistled and called me over to the boat he was working on. I thought he might have changed his mind and wanted to earn his $95/hour and take a shot at my motor. NOPE! still not interested, BUT he knew a retired Yamaha certified mech that was good with older carbed engines and gave me his phone number.

I called the retired mech (Travis) and told him my sorrows. He said he would try to help. He loves old Yamahas and bought into my troubles. We agreed on a time to meet and he would bring his tools, meters and years of Yamaha experience.

More below.

[77SceptreOB]

So Travis picks and prods at the engine. Starts then cuts off, revs, etc while I assist as his helper and boat driver.

[77SceptreOB]

So we did the following repairs:

1) Replaced 3 ignition coil assemblies
2) Replaced all 6 spark plugs
3) Rebuilt/Cleaned one of the 3ea 2-bbl carbs (One bbl was completely clogged)
4) Adjusted and synchronized all the carbs (3)
5) Adjusted the TPS (Throttle Positioning Sensor) - It was way off

Total parts bill = $293

Total Labor = $220

Total Bill = $513

[Bigshrimpin]

You can't beat that!!

[77SceptreOB]

The results were OUTSTANDING!!

The chart below summarizes the New performance:

RPM SPEED (MPH) GPH MPG
800 4 1.0 idle
3900 28.5
4000 29.1
4100 30.5 10.5 2.90
4300 32.3 11.5 2.81 (Optimal Cruise)
4600 35.2 13.3 2.65
5000 37.3 15.0 2.48
5400 40.8 18.4 2.22
5700 42.8 20.3 2.11
5800 43.3 21.2 2.04 (WOT)

The "Hole shot" was VERY strong with this 17" pitch prop.

I was totally impressed by this tuned up 27 year old 2 stroke Yamaha motor and had to share this.

Test conditions:

30 gallons of Fuel
Light load
One driver only
Aluminum prop in good condition ( 3 blade x 17" pitch)
Head Temp 140*
Engine water temp 130*

[NoBones]

Originally Posted by 77SceptreOB

I called the retired mech (Travis) and told him my sorrows. He said he would try to help.

Retired !!! at what 45 ??

I need to find a new profession...

[DonV]

Jim that's BS!!! You are just pulling our leg!! There is no way you pulled that off for a smooth $513, most boat repair shops don't get a "woodie" until the cash register hits at least $1,500!!! When it gets to $2,000 and up they are in full happy mode!!

Seriously, you know you do have to maintain these more than once every 25 years???

[gofastsandman]

Originally Posted by NoBones

Retired !!! at what 45 ??

I need to find a new profession...

Me too.
Roll eyes.

[Bigshrimpin]

Add in a new set of fuel pumps and you'll have refreshed the entire fuel system on that motor. The ethanol fuel ruins my Merc Fuel Pump Diaphrams. After about 2 - 3 seasons they get hard stiff like potato chips. Just something to consider if your fuel pumps are 27

[77SceptreOB]

Originally Posted by Bigshrimpin

Add in a new set of fuel pumps and you'll have refreshed the entire fuel system on that motor. The ethanol fuel ruins my Merc Fuel Pump Diaphrams. After about 2 - 3 seasons they get hard stiff like potato chips. Just something to consider if your fuel pumps are 27

Thanks for the thought. I actually replaced BOTH fuel pumps three years ago. I know that blows Don's logic that I don't do any maintenance. HeHeHe! I replace the Empellor every 10 years whether it needs it or not...LOL!