Please look at my Yamaha plugs

[yammie15]

I'll write on the side of the boat!

[yammie15]

Before I get into the Idle Screw project, I'm wondering about, as someone suggested, a sticky piston ring. Is there something I can squirt through the spark plug hole that will loosen up a ring: carb cleaner? DW-40? PT Blaster? kerosine? dynamite? ...just avoiding work here, but maybe...

Bry

[TownsendsFJR1300]

A compression test should have been done already to get an idea on the health of the top end. Both cylinders should be with 10% or so of each other.

A leak down tester as well, can let you know how well the cylinders/rings are sealing.

IF, one (the problem, lower cylinder) is much lower, you have a direction to go. If its close to the other, thats not the issue and your chasing your tail..

There are some additives you could try but your kinda jumping the gun and fixing something you don't know(compression/rings) are even broke.

IMO, verify compression is as it should be first. Rule that out or in.

We need compression, fuel/air and spark..

[TownsendsFJR1300]

Now, if that cylinder IS LOW, adding a little bit (couple of tea spoons) of oil into the combustion chamber will help seal the cylinder/rings. Compression will rise when re-checking.

[99yam40]

shock treatment of Yamaha's ring free additive or seafoam will usually help a stuck ring if carbon is what has stuck it.

But i agree with the compression test needed

[yammie15]

Wish I had the tools. I can try to borrow one put I could spend days here, looking. Maybe all round faster to order one from the US and have it floated over. Can anyone recommend a good but inexpensive Compression Tester that will fit my engine? And, while I'm at it, a good repair manual written for the beginner and what's this device for testing the ignition system?

Thanx,
Bry

[TownsendsFJR1300]

This is the compression tester I have, may be over kill for you;

Amazon.com: OTC 5606 Compression Tester Kit: Automotive IMO, a very accurate product..

And the spark tester tool;

99051130023 Echo Pet 4000 Pulse Ignition Checker KV Tester Oppama New Tool | eBay

This strictly checks for spark only, the strenth of it, etc. You can adjust it to check the strenth of the spark. It can also be installed and have the engine running to see if your loosing spark at a certain RPM. Again, IMO, it works very well, well worth the investment..


The Yamaha manuals are somewhat more advanced and often don't cover the basic's and tend to assume your a marine mechanic.

Someone else will have to chime in re a more basic manual, Chiltons or ?

Just narrowing down the problem with these tools will be a BIG help in pointing you in the right direction to go. If there's no/little spark on the lower cylinder vs the top, you know its ignition. You can visably see the spark jumping across the electrodes. With the compression tester, you can easily get an idea of the health of the top end of the engine. It won't tell you if you have a lower sealing leak, but that's not common...

[yammie15]

Thank you for this information.
Bry

[yammie15]

Compression tester on order... Please stand by!
Bry

[yammie15]

Just wanted to keep the thread alive, though my compression tester has not arrived yet. I did try flushing the carb with cleaner but was reluctant to dismantle because I don't have a gasket kit. I drained the gas out and replaced the drain screw. Kept pushing the carb cleaner through, let it sit an hour, drained, and repeated. Didn't seem to make a difference and I noticed that the lower plug is starting to turn black again.

what I find weird is, I drove the dingy to the dock at about 8:00 in the morning, with it missing and sputtering all the way. Left it tied up while I took the bus into the city for the day. When I returned, about 5:00 in the afternoon, it started with one pull, no choke, and ran smoothly back to the sailboat. It was sitting in the tropical sun all day. It started me thinking about condensation, but I can't figure it.

Any ideas?

Thanks everyone...
Bry

[TownsendsFJR1300]

Have you checked as many wiring connectors you can get to including the ground wires, etc? I don't mean just looking at them but un-plugging, un-bolting, cleaning grounds, etc.

Visably checking for any bad conections/loose wires?

If you have just a little bit of corrosion, especially with moisture, it may have dried up some during the day and give you a good connection (IE, some part of the igntion system working/not working). When damp, its shorting out...

Just a thought...

[ausnoelm]

Flushing the carb bowls out is useless, a complete waste of time, it does not CLEAN the carbs, sprays and cleaners are best left on the shelf in the shop if you are not going to dismantle the carbs.

[yammie15]

Thank you Scott, for your patience. Let me have a look at the connections. Everything looks clean and solid, but as you suggest, that might be deceiving. This will give me something to do will I await the arrival of the compression tester.

ausnoelm: Yes... I figured as much but I was afraid that I might not be able to re-assemble the carb and I need my outboard to get to shore in the mornings. I'll see if I can purchase a gasket kit here, or get one imported before I pull the thing apart. Then hope for the best.

Thanx all...
Bry

[TownsendsFJR1300]

Most of the time, you can get by without a carb re-build kit.

When the carbs crap up, the main and idle jets clog.

Simply pulling the float bowl, PULLING, INSPECTING each jet(so you an actually see thru them), is necessary.

Removal of the float and needle to ascertain there's no crap under the needle seat doesn't hurt either.

As noted above, shooting carb cleaner just into the bowl, won't clean a jet. The bowl may be nice and clean, but won't clean the jet. Those jets, especially the idle jet have very, very small orifices..

You may have have some grit in there causing the needle to NOT seat, thus causing excess fuel and flooding(fouling a cylinder). Inspect the float needle seat, it should be nice and smooth, NO ridges....

[TownsendsFJR1300]

Just a side note, back in 2005(or so), my newish motorcycle, (a Yamaha FJR1300cc sport touring bike) was acting up intermediately. Being it was under warranty, I brought it to the shop. The Techs, mama Yamaha in Ca, couldn't find the issue.

I went on line, to an FJR forum. I found a thread that year bike, ONE connector, under the fuel tank, was prone to water intrusion/corrosion.

Lifted the tank, found the connector, sure as s..t, nice and green inside!!!

How it ran as good as it did, I don't know.

Cleaned the green goo out, dilectric greased the connector, re-assembled, fired it up, ran like a top!!

You couldn't see the corrosion without pulling it apart. The bike wasn't 2 years old, not in the marine enviroment but that connector corroded...