Outboard Rebuild

[Charlie]

I traded my 6hp Mercury and some cash for a 15 HP Honda. Didn't look at the engine before hand just did the deal. Anyway got it home and there was emulsified oil in it. Changed the oil and ran it and found water in the oil. There was a white granular substance around the head gasket so I figured it needed a top end job. Never done one before but how hard can it be?

I got all the parts and put it back together. Had the carb professionally rebuilt. Now it won't start. So I checked the three items needed to for combustion. 1) It has spark. 2) I bought a compression tester but it won't fit. I'll have to wait till tomorrow to get an adapter. In the mean time I checked the compression with my finger and it feels pretty good, and 3) I sprayed some ether into one of the plug holes and it didn't give a hint of wanting to start.

My arm is now tired. I can't get the engine to start and I have had an evil thought -- take it in and have it fixed. I really don't want to give up. Here are some questions.

Could the ignition timing be bad? It is only a 2 cylinder. I have the manual and it doesn't say which cylinder is #1. I think I got it right. but if I have it reversed will the spark not fire off at the right time?

Any other ideas on what to check?

[Florida Mike]

What little I know about Hondas outboards you can put in a thimble and never know it was there. But basically they are overhead cam or at least the one I had was with ignition fired under the flywheel. You could conceivably have it firing the piston that is just finishing the exhaust stroke. Generally the number one cylinder is a top cylinder. You might consider taking the timing belt off of the cam and carrying it 180°. If you do this turn the engine through three or four revolutions with your hand on the flywheel. This makes sure you have a set it up so that the valves clashed with the prison. Good luck, just my two cents, Mike.

[ausaviator]

I'm confused (for you). If it has spark and you put in some fuel, you'd think you'd at least get it to fire! Maybe a little more fuel down the holes might help.

[Charlie]

If the timing belt wan't installed in the correct spot would this cause the engine not to start.

[sailorchic34]

In a Word YES!!. Timing has to be close for the engine to even sputter. Its very easy for someone to set the timing 360 degrees out on the crank shaft. If you have spark, air and compression then timing is off. Could also be the firing sensor thingy (there's always a thingy involved) might be miss-adjusted too. So you have valve timing and spark timing to check...

[Therapy]

Originally Posted by Charlie

If the timing belt wan't installed in the correct spot would this cause the engine not to start.

If you removed the cams/valves to get to the head gasket - I am assuming here - then you probably moved the timing chain. If you did not mark it and make it "the same" on reassembly it is probably your issue.

You can damage things pulling it through if valves hit piston tops. Probably not or you might have felt/heard it by now.

[Boatguy30]

Put your finger on the top plug hole and roll the engine clockwise by hand. When you fill air blowing out it's on the compression stroke #1. Roll it till the marks on the flywheel are on the mark on the head. If the cam pulley mark is not matching the flywheel it's not timed right. This is the spec for many 2 cylinder 4 stokes. Possibly not for the Honda 15.

[Therapy]

Charlie,

I don't know if this will help but I have a BF15A right now and the manual says:
Timing belt installation

1. Install the special tool on the crankshaft by aligning the keyway groove with the woodruff key.

NOTE: make a reference mark on the outside of the special tool to indicate the keyway location

2. put the flywheel nut on the crankshaft, and hand tighten it to prevent the tool from slipping.

3. rotate the crankshaft below TDC and install the cylinder head assembly on the engine.

4. install the cam pulley and rotate the cam pulley by hand until the T mark aligns with the T mark on the breather cover.

5. Rotate the crankshaft until the reference mark on the special tool aligns with the I mark on the stater cover and install the belt.

The special tool in the pic looks like a hex nut of some sort. No threads visible but it fits on the tapered, keyway cut drive shaft. This makes me think it is indeed a specially tapered hex nut "thingy". Part # 07923-ZA00000 (5 zeros) Yep - gotta be special.

Anyway. Thats all I have.

[Charlie]

I got the OB running. I had not aligned the crankshaft when I put the timing belt on only the cam shaft. When I got it back in order it still wouldn't start. Changed the spark plugs and it fired right back up.

@ Sailor Chic Thanks for the info. I don't think the timing "Thingy" is off. The camshaft is exactly 360degrees off for each cylinder. Now it sounds like the timing is off by a tooth or two and I have to redo the valves and timing belt. Still not sure which is cylinder one. I am assuming it is the top one but don't know why I make that assumption.

@ Therapy thanks for taking the time to copy the info from the manual. I had not aligned the timing on the crankshaft when I installed the timing belt and had moved the position when I put the flywheel on. BTW a long screwdriver or a long thin prybar allows you to remove the cam shaft bolt. To remove the flywheel I bought a $15 tool at autozone can't remember the name but I had to buy some extra bolts to fit the Honda threads. It is hard to align the crankshaft to within a tooth I am going to study it again today to see if I am off.

@Boatguy30 -- I tried that but ended up getting a compression tester. Thanks for your comment