hard starting outboard

[oldiesrocker2001]

I have a 4hp 4stroke kicker motor on my boat. There is usually a week between sails. Three outings ago I noticed the motor surging a bit under load even though I had blown out the venting system to my below-deck tank setup. The following week I came with about 6 gallons of fresh fuel with a strong dose of fuel stabil and replaced the fuel with the new stuff(after pouring the old into my tow vehicle) Motor ran beautifully the rest of the day - granted, on an average daysail, the motor runs for a couple of minutes away from the ramp and set the main; then again on return (it gets more use then as I often need to circle a number of times waiting for a ramp to open up).
The last outing, I couldn't get it started at all at the outset of the day. Pushed off by hand with a little help and came in under sail to beach it. While it was beached I pulled the cowling and noticed a bit of fuel dripping out of the intake while still tipped up. As I had left it up and tipped with choke open and throttle wide open, this makes me think of flooding as a possible problem. I wiped the residue away and the motor started on the second pull. Is it possible the extreme heat and humidity caused a vapor lock type of condition we used to encounter in our old carbureted cars? I made sure the tank was as full as possible to prevent any excess condensation.

 

[Stu Jackson]

In electrical issues it is always (99 & 44/100ths%) connections.

With your issue, it is the same for carbs.

Brian, one of our fine moderators here, had a similar issue a month or so ago. Took two pages of discussion to get him to do his carb.

Good luck.

http://forums.catalina.sailboatowners.com/showthread.php?p=1121060&highlight=carb

Go to the top and page 1 for the full story.

Only other issue I can recall is: kill switch wiring fault.

 

[oldiesrocker2001]

Thanks, Stu. This is about the 4th season with this carb. I originally bought the engine used and it worked fine for several years. At that time I was using the conventional wisdom of running the engine dry each day. I then had a similar problem to the current one and the replacement carb cost more than the motor did. Before I had the carb replaced I had replaced the coil/module since I couldn't be sure if it wasn't a spark problem while pull-starting it.
Each season at startup I now run the engine and spray carb cleaner into the intake carefully for a while. Since I always use fuel stabilizer, I don't run the engine dry anymore ( I guess because that method was no guarantee of a worry-free day). I'll take a look at the kill switch wiring anyway this week, but it still seems like a fuel issue. I've never rebuilt a carb from an outboard before but I don't suppose it could be much tougher than changing jets on an old Holley between rounds at the track... Just can't see being charged 3-4 hundred for another carb.

 

[celticwinds]

I would not recommend fuel additives as a cure all. Close the vent on your fuel tank when not in use to prevent condensation in the tank. Sounds like you flooded the engine, so for sure replace the spark plug with a new one. You can use some type of suction to take a sample from the fuel to check for water in the fuel. Any water will be in the bottom of the tank. Remove the spark plug and lay it on the engine somewhere to ground it and crank the engine and check for a blue spark, check to see if the plug is dry, or fouled. If the engine is starving for fuel the spark plug will be dry. Make sure the choke or primer system is working correctly. Make sure the fuel line bulb is holding pressure. Looking at the spark plug will usually give you a clue as to what the problem is. Always start with the most simple things first. A new spark plug is inexpensive and should be replaced first. Make sure fuel is getting to the plug at start up. Does your engine have a choke or a primer system?

 

[Rich Stidger]

I will give you any odds that your problem is the carb. Always run it dry at least at the end of each day. Use Stabil with every fuel purchase. A friend who is a professional outboard mechanic tells me that the best way to clean a 4-cycle carb is by using an ultrasonic cleaner. This is because the passages are so small. Personally I have successfully cleaned carbs with a dunk solution and blowing them out.

The symptom of fuel coming out of the carb intake suggests to me that the float is not shutting off the fuel and it is flooding. A friend with a no-restart problem found that his float was damaged by the ethanol gas we buy. It dissolved the coating on the float so that it absorbed gas and got heavier. It was a 1970's vintage outboard.

I have considered going to my local airport and buying aviation fuel that has no ethanol, but I have not as yet.

 

[Ron20324]

... I have considered going to my local airport and buying aviation fuel that has no ethanol, but I have not as yet.

I did that, but put a tag on the outborad tank that it has leaded fuel (do not put in a highway vehicle, I'm told you'll kill the catalytic converter).

 

[Rich Stidger]

I did that, but put a tag on the outborad tank that it has leaded fuel (do not put in a highway vehicle, I'm told you'll kill the catalytic converter).

Ron,

Did the use of aviation fuel help?

 

[sailingseadragon]

Most likely it is carburetor problem - I will not say that your problem is a result of having ethanol in your fuel, but for what it worth, ethanol free gas will result in few carburetor rebuilds. If you are interested finding a station near you selling ethanol free gas try

http://www.buyrealgas.com/#

Garner

 

[oldiesrocker2001]

Thanks for all the input guys. I took the boat out for a late afternoon sail yesterday (our favorite time of day). While I came prepared to replace plug, suction up some fuel for examination of water, check connections, as well as including a can of ether in my kit, the engine started on the second pull both at the dock and again on the water on the way in.
No water was visible on the suctioned up sample from the bottom of the tank but on my next time out I'll be able to read the plug before launch as I shut it down after a couple minutes at idle at the dock (getting too dark to fool with it just then) yesterday.
It seems to have been an isolated incident but I can't take it for granted.

 

[Rich Stidger]

Unlike a cut on your finger, mechanical things don't heal by themselves. you may have gotten a reprieve, but I think the problem will return.

 

[SeaTR]

oldies,
I'm going to 'second' Stu's suggestion / perspective...it's most likely the carb (ethanol fouling). I removed the carb bowl on my 3.5 Hp 2 stroke Nissan kicker and used Seafoam to clean the bowl, float (Seafoam is OK with plastic), and squirted some into the fuel pickup jet.

I let the jet injection sit for 5-10 minutes for dissolving action, then thoroughly used pressurized air (standard 120 psi shop compressor) to blow out the fuel pickup jet line (and any idle jet passages that you may have as well).

Reassembled and tested...worked like the proverbial "champ".

I don't think you necessarily have an "isolated incident"...

Good luck with your troubleshooting efforts.

 

[Ron20324]

Ron, Did the use of aviation fuel help?

Can't say. The motor had not been used and fuel sat in the can for a year before i used it. Motor started on the second pull, so i assume the carb was clean before the av gas?

 

[Rich Stidger]

Can't say. The motor had not been used and fuel sat in the can for a year before i used it. Motor started on the second pull, so i assume the carb was clean before the av gas?

Probably was clean. The real test is to find out if it stays clean with the leaded non-ethanol gas. I suspect it would.

 

[Brian D]

As Stu mentioned, my final resolve was to remove the carb. Had to do it while the boat was in the water. As careful as I was, a one minor part went overboard. However, my Pilot Jet was clogged, but the Main Jet was fine. I also had a huge glob of gunk in the bottom of the float bowl. It was clogging the fuel drain hole.

I let the jets sit in Sea Foam for about an hour. When I started the liquid was clear. When I came back if was foggy. I also used the smallest sewing needle to clean the holes because I had no compressed air. The needles just fit but would not go all the way in and that was fine.

End result was a smoother running engine. But believe me, I was scared crap-less that I would really foul things up. If this was an older motor, ok, no problem. But it was just a few years old and still under warranty. So you can guess my concerns.