honda 20hp

i have a honda 20hp 4 stroke tilt and trim 2004 model . it started fine till a few days ago then when i started it the outboard became uneven for about 10 seconds then stalled .it runs for 4 seconds thats it but i noticed there are loads of smoke like you have on a 2 stroke engine and it smells like a 2 stroke .i know the fuel is more than 6 months old . before this happened it run fine . i have sent for new plugs and i will put new petrol in the tank . just incase this does not work any ideas .i have noticed on the bottom of the out board there is a small hole and there is oil there just a small amount it is only there when i try to start it . the small green light is on and it pumps water fine it goes in and out of gear ok . i have 2 stroke engine with fuel made i just hope my brother never put 2 stroke in it when i checked it it looks fine

Hi weejohn,
Sorry you're having troubles. Well...if it turns out that your fuel is OK....there are a couple of things you may want to try even if the fuel is the culprit.

First off, have you cleaned out the "fuel chamber"? The fuel chamber is a black reservoir that is plumbed into the fuel system between the fuel pump and the carburetor. It is housed in a black, round holder that is attached to the engine oil dipstick tube. To clean it, simply remove the fuel lines from it and then slide the holder and chamber up and off of the dipstick tube. A little lube on the tube (hey!...lube on the tube!...I made a poem!) will help here. For reference see items #4 and 2 in the parts page link below.

http://www.boats.net/parts/search/Honda/Outboard Engine/2004/BF20D4 SRTA/FUEL PUMP (2)/parts.html

Those chambers will collect water over time and need to be drained out every so often. Just keep shaking until no more liquid comes out and then re-install on the engine. Prime as usual and see it that helps.

As far as the oil small oil leak you see....make sure that the oil filter in on good and snug and has no holes in it. I have seen them punctured accidentally and I have also seen one that had a hole in it right out of the box! With the engine cover off, have someone crank (electric start?) the engine while you watch. Pay particular attention to the filter and dipstick tube area to see if you can tell where it's coming from.

One other thing to check would be to make sure the timing hasn't jumped. These engine don't usually have timing belt problems but yours is over 10 years old and it may have stretched a bit in that time. The timing marks on this one are fairly prominent and it's easy to see if they are not in alignment. Basically the little "dots" on the cam sprocket and the flywheel should line up...or point at each other...with proper cam timing. I've found this isn't "perfect" and, on some engines, they won't be EXACT but...they should be VERY close to perfect. If there is misalignment over 1/8", the belt has jumped a cog. An engine will usually start run (poorly) if off even by 2 or 3 cogs of the belt so I'm thinking yours is PROBABLY ok. It's just a good idea to check.

If it turns out that it was the fuel (and your brother:~), opening the carburetor drain screw and then pumping the primer bulb to flush out the fuel system should get you going again. Although it may be pretty smokey in your area for a while once the engine fires up.

Good luck and let us know what you find.

i have done what you said regarding the fuel system i have put a new oil filter and new oil as well i done a compression test and on one cylinder which was 154 psi it started raining i check the other one during the week lol . is 154 psi low or ? when i get new spark plugs and fresh petrol i get back to you and let you know if all is well

154 is a tad low....But know that it's not uncommon for an engine that has a lot of use and it should start and run just fine with that amount of compression. I would worry if it fell below 140 or so but they will run at 120 and even lower.

Did you hold the throttle fully open when you took the pressure? Were both plugs removed? If you forgot to do those things, go back and retest with the throttle wide open and both plugs out. You should see the pressure come up significantly. An absolute TRUE compression test would be to place the outboard in a test tank (trash can) and perform the test as prescribed. Having the outboard in water will simulate the exhaust backpressure it experiences in actual use.

Also, contrary to what many think, an engine that is out of time can have fairly good, somewhat even, compression if it isn't too far out of time.

You can tilt the outboard WAY up until the pistons are vertical and add some oil to the cylinders to do a "WET" compression test. Only add oil to the cylinder being tested. The piston needs to be vertical so that the oil spreads out on it's top. Give it a few minutes to do that. Rotate the engine slowly a couple of revolutions to remove excess oil from the cylinder and install your gauge. Then...remembering to hold the throttle wide open....check the pressure again. If it comes up well higher than it did on the "DRY" test....that will tell you the rings are worn. Again, normal for an older, well used engine. Or, you can perform a cylinder leakdown test and that will usually tell you where the compression loss is and at what percentage.

I hope you get her goin' ok.

i changed sparkplugs done oil change and new fuel and done what you said regarding old fuel and water in carbs the engine starts ok now but when i give it high revs in neutral there is a backfire it goes in and out of gear ok . any idea how to solve the problem . i dont know when the engine got a full service i am the new owner of 3 weeks

What do you mean by "backfire"? Is there a "pop" out of the exhaust? Or, is there a "pop" out of the carburetor? This engine has a rev limiter for keeping you from overspeeding the engine in neutral. Could it be that?

If it is truly backfiring out of the intake...or exhaust.... then I would first look at cam timing...as I suggested before. If The engine is in time, Then you need to take off the valve cover and inspect the valve actuating mechanism. Check that the valves are in proper adjustment and haven't gotten too tight. Look for any broken valve springs. A broken spring will leave a valve hanging open. If the timing is good and the valve adjustment and springs check out then it's possible you purchased an engine with a "feathered" or burned valve. A cylinder leakdown test would confirm a valve that is not sealing.

If the valves were never adjusted and ran tight for a period of time, THAT is what usually burns valves. So, if you find the adjustment tight...and you adjust them properly....and it still backfires....that is what has happened. Pulling the head and doing a valve job is the only solution for something like that.

But, the carburetor COULD also be the cause. If it is popping out the exhaust, then the carb may be flooding the engine with too much gas and it is vaporizing and igniting in the exhaust manifold. Highly unusual in an outboard due to the water cooling the exhaust.

It is much more likely that, if it is a faulty carb, it would pop out the intake. This would be because the carb is not delivering enough fuel and you are getting a "lean pop" or backfire out of the intake. The solution is a carb rebuild.

Can I tell you how to fix it? Not until you figure out what is causing it.

Did you get any answers to your compression question that you posted?