Started the decarb on my 1967 Johnson 80hp tonight (see video)

[BonairII]

After doing a ton of reading on the many different decarb procedures...I decided that I wasn't going to wait any longer. (Talked to PO and he had never done a decarb on it)
Warmed up the motor this morning then pulled the plugs and heavily sprayed each cylinder(at TDC) and let the motor sit all day.

Just started it up about 30 minutes ago and let the motor start sucking up the gallon of Seafoam/Premix. Lots of smoke, so it's def doing some carbon removal.

The video is about 5-10 minutes into the first round of the decarb.

http://www.youtube.com/watch?v=vzqgktoIOl4


No wind, so most of the smoke is going upwards instead of engulfing the neighbors

Update: Just ran her another 10 minutes and the smoke is still coming out thick with no signs of letting up. Def must be a lot of garbage in there. I've only got about a 1/4 gallon of the "mix" left.

Probably going to have to mix up another gallon and continue running it tomorrow, if the smoke doesn't stop.

Second Update: Ran her for the third time and the smoke just keeps coming and coming. I went thru the gallon of "mix", so I'm done for the night. Going to mix up another gallon and do it again tomorrow.

 

[dazk14]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Don't get too excited about the smoke. The Seafoam product itself smokes. Not unlike putting too much 2 stroke in your mix. It really works better if you can run it after it has set. The product loosens the carbon connection and the added heat and turbulence helps to blow it out.

What you're doing is still much better than nothing.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

I'm now running the 2nd gallon of "mix"....and she's still smoking quite a bit as you can see in the video.
I've noticed that as the decarb progresses, that my lowest idle is a bit faster than it was 'pre-decarb'. The idle is too fast to shift into gear now(assuming motor was in the water).

http://www.youtube.com/watch?v=dxjYNHbwVek

 

[dazk14]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Well, that's a good sign. It's possible the rings have freed up, the exhaust ports are clearing up and it's making a little more power. Looks like you're in Los Angeles.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Just finished running it again for 10 minutes. I'm still getting a good amount of white smoke out of the upper exhaust hole, but now I'm getting a lot bluish smoke out of the exhaust near the prop.
I changed to Pennzoil synthetic 2-cycle oil today(Walmart was out of SuperTech), I wonder if that's what's causing it. It would be odd though, cause I thought synthetic oil smoked less. My motor normally smokes very very little.

My compression on all 4 cylinders was 90psi (mistakenly been doing it with engine cold). I'm hoping to get 100+ after the decarb(checking with engine warm).

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Well, I've now finished the 2nd gallon of Seafoam mix and she is STILL smoking steadily. Anyone heard of a decarb going on this long?

http://www.youtube.com/watch?v=KhO7HdBEBiE

 

[inthedirtagain]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

I haven't fogged my 66 100-s, but I'm on my 2nd can of SeaFoam shared between 4 tanks of fuel. I've tried to let it idle to clear out my slow jets, but then I also make sure to run WOT across the lake. I've noticed that once I get out and open it up, it generates significantly less smoke. I believe these older motors tend to run a little rich down low, so that may be contributing to your smoke at idle. Rev it up once in awhile (neutral) and try to clear everything out. You may notice reduced smoke levels. My manual recommends doing this to "blow it out" when carb tuning or cleaning.

 

[kfa4303]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

HI BOnairII. That's plenty of seafoam mix. Now you need to get the boat on the water and run the motor at WOT with normal fuel mix for a while so that the the motor can get up to temperature and burn off the crud. Check the plugs at the end of the day to see how the look. They should be ok, but you may need to replace them if they got cruddy. Running on muffs is ok, but you really need to be on the water to set the lo/hi idles properly. The rpms may be a bit high now b/c you have insufficient exhaust back pressure. When you get to the water, try and dial in the lo speed idle at the dock. Have fun. Stay down wind of the other boaters while you're getting the smoke out. You should notice a lower overall idle and smoother engine performance in general thanks to the sea foam.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

The rpms may be a bit high now b/c you have insufficient exhaust back pressure.

Actually, it was able to idle pretty low on muffs prior to the decarb. The RPMs started to increase during the decarb. I'm hoping the increased RPM is a sign of the rings getting cleaned up.

Plugs are dark right now, but plugs seems to be ok. I'll be picking up some plugs just to be safe. I've been using A/C Delco plugs (NAPA didn't have Champions, so they recommended them)

Going to warm it up tomorrow and check compression.

Hopefully, I'll be able to get the boat on the water on Sunday.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Checked compression and I'm not pleased with the results at all. Pre-decarb it was 90psi (cold). Warmed the motor up today(battery was charged last night) and got around 82-85psi for each cylinder.
I have no idea why the numbers went down, unless the carbon was actually helping compression.

 

[kfa4303]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Hello again BonairII. Excess carbon never helps a motor. You're doing the right thing by decarbing the engine the way you have, but you really need to get it off the muffs and get in on the water and open it up to WOT ASAP. Strange too that the idle would go up too? You should be able to manually dial down the idle to put it in to gear, if need be. As for the change in compression, it's not a huge change and it that just be due to the gauge itself. Check it again after you've had a chance to run her at WOT for a bit. I would also highly recommend tracking down some proper Champion plugs. It's what these old motors were built for, and there can be some errors in compatibility between brands. Try and run her at top speed for twenty thirty minutes on the open water and report back. Hang in there. You're on the right track.

 

[inthedirtagain]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

If there is carbon build up on the dome of the piston, it will raise compression ratios because there is less combustion space. Its basically like shaving heads and using thinner gaskets to increase compression slightly.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

I just realized that the choke was closed when I did the compression check....would that affect my numbers?

 

[freddyray21]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

I just realized that the choke was closed when I did the compression check....would that affect my numbers?

NO it is a common misconception that the throttle has to be open all the way on a 2 stroke to check compression. This is not true so the choke being closed does not affect compression.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

The choke butterflies being completely closed wouldn't affect how much air was being sucked into the cylinders? That sucks then.

 

[freddyray21]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

As I recall that is a low compression motor. If it runs good then leave it be.

 

[Sprky]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Cold compression numbers are always higher that hot numbers. Looks ok to me.

Go to the lake and run it, see if the decarb job made a diff.

Let us know.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Cold compression numbers are always higher that hot numbers.

I would've thought it was the other way around.

Going to drop boat in the water tomorrow. I'll let you know how it goes.

 

[inthedirtagain]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

didn't make a difference on mine hot or cold. I was told that mine was a low-compression motor, too. Supposedly only having around 110 when new. Wish there was a way to verify this from a manual, or something.

 

[BonairII]

Re: Started the decarb on my 1967 Johnson 80hp tonight (see video)

Update: Ran the boat on the lake. It ran pretty darn good. I ran it with the same plugs that were in during the decarb(but I brought 4 spare(slightly used) plugs just in case).

Ran at WOT for awhile, then fished. A couple times after fishing, I started the motor and it died after 5 secs or so like it ran out of fuel. Then it would take a bit of cranking to get it to start. Not sure what it might be.

Overall...it ran really well. No sputtering, misfires or any of that nonsense. Seemed pretty 'peppy'.
I got it up to 31mph with 2 of us on the boat(including 13 gallons of fuel, and some misc gear). Water was tad choppy, too...so I see that as a little bit of improvement in the speed category.

Not really going to be able to really assess my speed 'issue' (if indeed, it really is a little slower than it should be) until I get a tach installed.

Fuel consumption seemed to better than normal. Could the decarb have improved gas mileage?

http://www.youtube.com/watch?v=4X-eNw8VKa4