Chrysler Sailors Forum

Hey guys, what do you think would cause an outboard to vibrate inordinately like it was "skipping"? We were in plenty of water, and it started while going fast. After a short time, it was jarring the boat while going really slow. Prop looks fine and isn't loose. Any thoughts? Thanks in advance!

Ethanol. REDUX has a 8hp Nissan that at idle was so quiet and smooth running we actually left the boat twice last season with the motor running. This year the thing has been very unreliable, starting, idling and running. I replaced the fuel from last year with "fresh" gas. Got a flyer from West Marine yesterday and noticed an ad for a gas treatment for ethanol enhanced fuel. Read the owners manual today, I running to WM to pick some up.

That additive is good stuff, and at the rate you mix it into the fuel that bottle will last forever ! When I sent Franz a pic of my split fuel pump diaphragm he said "you use ethanol don't you". Seems the ethanol is hard on rubber, and it also causes moisture problems when left in the fuel tank.

Have seen an air leak in fuel cause that problem with a two-cycle
outboard. Intermittent rough running that had us change spark plugs and try different shaft angles to stop what we thought was prop cavatation. After finding a small split in the plastic fitting at the fuel tank the problem was solved.

My Mechanic here in Ohio says to unhook the fuel run all the gas out of the engine when you are done for the day.. With the ethanol gas it will just gum up and rot out the carb. Then we have costly repairs. Also do an additive to the tank as well

I like everything above and would like to add to the list and repeat some too I'm sure.

1. Bad fuel
2. Water in the fuel. Add an in fuel line clear fuel filter.
3. fouled spark plug. Pull all the plugs, Clean the plugs with an old toothbrush and WD40, Replace plug(s) if worn. Re-gap the plugs.
4. Check compression with the plugs out, maybe broke something inside. (I doubt this one but it's possible.)
5. Check fuel line, you could have a small hole and your drawing in some air intermittently.
6. Dirt in the fuel system. (Again add a clear fuel filter to the line)
7. Prop out of balance or loose. (Looks like you checked this already)
8. Inspect impeller, maybe it broke apart on you and the chunks just don't go through an engine well. (No that would be a cooling system issue not a vibration issue)

With the spark plugs out, spray some of that WD40 in the holes. Put the plugs back in and start it back up. WD40 will work like starter fluid and the motor will run longer than you think with no fuel line attached. This trick sprayed into the collaborator will work as well and clean out the little jets and such while it's at it.

Oh, always keep the fire extinguisher close by when using the WD-40 trick and don't spray it with the motor running. Safety first, you have a lot more sailing in your future and your eyebrows want to come along for the ride.

Thanks
Alan

I mixed some of the Ethanol stuff to the tank and managed to get a few drops in the fuel line before I attached it to the motor. Started first pull after priming and ran the way it did last fall.

Nice!

Alan

All good tips and even with the additive in the tank which only doubles the time before it separates I still run carburetor dry each time.

Good tips on the additive. Anybody know the name it sells under at West.

Jeff

All good tips and even with the additive in the tank which only doubles the time before it separates I still run carburetor dry each time.

That raises a question for me. I have a two-stroke. How do you run the carb dry? Is it just a matter of cutting the gas supply off and letting it starve out? Should I be concerned about lubrication during the starving process?

Any advice most welcome!

pull fuel hose and let idle when rpm goes up pull choke out.

STA-BIL Ethanol Treatment. I actually found the stuff at AutoZone at a few buck cheaper than West Marine. 8oz. will treat 80gal for $8.99.

Thanks Guys! Good info!

I've been using STA-BIL for the past year.
Ye ole Sailor 280 has been starting right up and running smooth, no extra attention has been needed
...knock on wood!

I forgot to mention that, though we did loose some power, the RPMs stayed steady. We used ethanol-free gas the first two times out this year. The incident in question occurred while running on regular gas with the marine additive in it. Most of last year Mike ran with regular gas and the additive in the tank. This year we're trying to stick sole-ly to ethanol-free as much as possible, and this was the first time we used reg gas this year. So hopefully it is the gas?

The real thing that has Mike (Husband) confused is that the RPM's stayed the same - while running fine and then when it started all the vibrating. Last year we had the motor quit due to ethanol gas - but before it died the motor sputtered and the RPM gauge was all over the place...

Beau/ "Emergency Exit", do you think that past damage due to ethanol could cause this problem to rather suddenly crop up?

Another question: can you always see the imperfections in the prop that would cause imbalance? Or is it necessary sometimes to have a pro find them? Thanks!

If you had a problem with ethanol gas when it started to act up you may need to clean some gunk out of the carb. or other carb. problem.

The ethanol type damage "could" cause something to suddenly crop up, such as the problem I had with the rubber diaphragm on the fuel pump splitting - one day the pump was fine, although damaged by stretching, the next day it tore and no longer worked.

If your RPM's stayed the same and you had a power loss (as in the boat slowed) or vibration, it almost makes me worry about the lower end or gearbox more than the motor.

Wonder (might be a good diagnostic) if you have the same issue with the motor in neutral same as you do in gear and running the boat along.

Very good idea EE.

That's a scary prospect (@Emergency Exit), but I'm glad you mentioned it. Will be messing with it this afternoon to see what can be figured out...

sauerleigh

I really like you avatar!

Sorry,,, back to your regular post....

Potomac Fever wrote:That's a scary prospect (@Emergency Exit), but I'm glad you mentioned it. Will be messing with it this afternoon to see what can be figured out...

I hated to bring it up too...good luck !

Just finished work on mine today. Major success! See that little tell-tale stream? Didn't have that before. Runs like a top! Woo-hoo!

Is the tell-tale the only place I should see water coming out? Should it be coming out with the exhaust as well?

Hey Mark, what's model and HP of the engine ?

Mercury 9.8 Circa 1980-81.

Finding pea sized gobs of oily muck (dirt) and dead bugs floating in the water after running it. Exhaust smoke coming out fine, especially when I'm sraying cleaner down the carb.

Water way is fine into the top of the water sleeve, got all the pieces of old impeller out of the system. Has a location for a thermostat, but none there right now.

With a few oily gobs of dirt and bugs coming out, makes me wonder if there should be some flow, but got clogged by the last guy running it through the mud. Just can't figure how it should flow through the water sleeve???

you should be fine if it only gets warm at the tell-tale if it gets too hot to put hand in that is when you worry.

meant to update sooner. ..

Well, Friday and Saturday after Mike flushed it with carb cleaner and put ethanol free gas in, it ran fine in neutral, and at various speeds in the driveway. So, still a little leery, we went out Sunday. After about an hour, nothing seemed wrong, she was running fine. So hopefully that was all it needed...? guess we won't know until we've gone out a few more times for certain.

Thank you everyone for all the ideas/tips! We really appreciate it![/i]