Johnson 18 Hp FD -16

[nelsoje67]

A little background first - I am new to outboard motors. I recently (a month ago) bought an old 14 ft Jon boat that included this outboard. I wasn't real concerned about the outboard, as the boat came with 2 trolling motors, and most of the public lakes around here only allow 10Hp or less or electric only. Well one troller crapped out on the lake and had to row back - so hence the urgency to try and get the outboard running. I bought it from a second party - so no interaction with the original owners. I cannot get it to run. I have had it run on 1 cylinder (old style spark test, plug to side of the block) for about 10 seconds then it died. So i bought new points, condenser's, coils and plugs and installed them last weekend. This time it ran for about 20-25 seconds (with the old plugs) after multiply attempts from the electric starter. Cranks great, btw. I have a few questions about the tune up.

1. The original inside cover sticker calls for J4J plugs and then there is a hand written note indicating J4C. The motor has J8C plugs installed. I tried it with the new J4's and it wouldn't start. So i put the old J8's in and then ran for the 20 secs. My father says J6's would be better than 8's.
- so what do you think? Dad made sure the new J4' plugs were gaped at a.030

2. I found a thread (http://www.outboard-boat-motor-repa... 5.5 HP 1954-1964 Ignition System Tune-up.htm) explaining the procedure to gap the points to 020 the adjust to 030. Well, we cant get the points at 20 when they are opening, .025 is as close as it gets. and then the procedure states to adjust them to .030?????

3 In the barrel test, after multiply attempts to start, the water had a lot of fuel/oil mix. There was a lot of messing with the ratio knob. Another hand written note on the covers says 24:1 mix/ 32 oz to 6 gals. I see a lot of discussion on this site about the proper mix, and i'm thinking that the 24:1 is a tad thick, I'm also guessing that a carb rebuild is in order, but for the life of me i cant figure out how to search Iboats for this model. I think Johnson's only go back to the early 70's on the model search for replacement parts.

4. I do not have a compression tester yet, so I have not checked the compression on the cylinders.

5. I am starting from scratch, so any advice or direction would be helpful, and appreciated.

Thanks
Jim

 

[RCO]

Points need to be at .020 (.030 is the spark plug gap) set with the rubbing block at the crankshaft key. You can tweak the bracket if you need to. I'm guessing these are Sierra points? Make sure you clean them with solvent after you set them. J4C is the correct plug, J6C is one step hotter, use those if you foul J4C's. Initial carb adjustment is 1.5 turns from seated on the low speed, and about 1/2 turn on the high speed. 24:1 is the factory recommended fuel/oil ratio. Carb kit will be the same as early 70's 18/20/25hp Johnson and Evinrude.

 

[oldboat1]

This might help: http://www.fiberglassics.com/library/images/2/2a/Evinrudeservice001.pdf (Evinrude and Johnson info mostly interchanges). The site you supply isn't bad -- think the reference to a .030 point setting might be a misprint, even in context of an initial setting. J4C is correct, set at .030. 24:1 is also correct. Set the points to .020 when the rub arm is at the highest point of the cam, then rotate the shaft 180 degrees and set the other side. Don't run J8 plugs as they are too hot. The knob you are adjusting is the air mix needle, as contrasted with the fuel ratio (oil/gas). Initial setting is 1 1/2 turns open, then adjust for best operation.

Get the points set correctly first (not sure offhand what the difficulty is). Points have to be squeaky clean as well as adjusted correctly.

 

[Crosbyman]

you need this ..

http://boatinfo.no/lib/johnson/manuals/1922-1964johnson.html#/0

http://www.youtube.com/watch?v=ga1Cjymj6ms&feature=youtu.be


http://www.leeroysramblings.com/johnson_E-FD_15_18hp.html

 

[nelsoje67]

OK, so its the weekend and I had some time to work on the FD-16 again. I set the points with the multi-meter technique that someone posted here, and It started! Now I have a few more questions. It will only start while giving it some throttle and will not idle. I have an old school timing light and the timing marks seem to jump around a bit on both cylinders. Some times a little before or right on. There is a about a 1/4 inch between the timing marks and it appears to always be between, or a tad before, but never steady like I would be used to seeing on an auto. Is this inherent to a 2-cycle motor?

Also, the plate that the coils and contacts mount to seems to move rather freely. Both set of screws from the plate and coils shoes are screwed into the ring below the plate. I get that it should move CCW for advance on the throttle, but don't understand why it would move so easily while rotating the the flywheel by hand when setting the timing. Makes it hard to get it exact constantly. I set the timing with the marks at about the 8 o'clock position. Does this sound correct?

I have not done anything with the carb yet. Someone also mentioned the the initial adjustments, low and high, by turning the screws in and then backing them off. Are these the screws that are linked to the lean/rich knobs on the front? I would have to remove the plastic hubs on the screws that are turned by the linkage, and then re-attach them to the screw after the adjustment?

She smokes pretty good, not sure if this is because of the fuel/oil mixture ratio, or because its a 2 cycle, or just because she's old and hasn't been taken care of. But, I got it to finally start due to the advice from this forum. so thank you all for that.

Thanks Again.

Jim N

 

[oldboat1]

progress, sounds like. On the magneto plate: shouldn't rock up and down if assembly is correct -- flat side of the retaining ring underneath faces up. If the mag plate rotates with the flywheel, it may be that the coils are too close to the flywheel magnets. Coil laminations have to be flush with the machined edge of the mounting posts (gives you the right gap between the coils and the flywheel magnets).

The carb needles can be set (initial settings) before the plastic ends go on -- try half to 3/4 open for the high speed needle, and 1 to 1 1/2 open for the l.s. needle (top one).

 

[HighTrim]

Good advice given so far.

Agree, the coil laminations are likely hitting the flywheel magnets from being out too far. DO not push them in too far either, or you will limit spark. THey have to be just right.

Also, always check compression BEFORE you spend any money on a motor. Always should be step 1. Definitely wont run well or start properly if 1 of the cylinders has 30 psi right.

 

[nelsoje67]

I checked the compression on each cylinder tonight and had 70 psi on both. I know its a little low, but this an inexpensive tester with about 12 inches of rubber hose from the gauge quick disconnect to the spark plug port. Also had to use an adapter with a rubber o-ring to threaded into the port, which the end of the hose threaded into with another rubber o-ring. So maybe(?) I lost a few pounds of compression due to hose expansion? Guess maybe I'm just trying to justify the low reading to myself.

Think its still worth messing with?

 

[oldboat1]

Not sure about that tester (might borrow one). Hey -- maybe $125 invested in parts? They are all usable on another period motor -- like a number of parts belonging to the 18 itself -- electric starter parts, for example. I would continue to play with it. See if you can get it up and running. Remove both plugs for testing compression, and crank until the needle stops moving.

 

[Crosbyman]

if points are good and adjusted coils new and condensers ok plugs sparking it sounds like fuel starving I have a FD that runs good at 70psi

re-verify all parts of the fuel supply route from the tank pick-up to the carb inlet ( try hand pumping the bulb in case the fuel pump is not working (bad check valves or diaphragms)

I just fixed up a $50 9.5's mdl 9622 square fuel pump that was reassembled incorrectly !! causing the engine to die out if I did not do the pumping myself) )


if fuel reaches the clean carb ok it should suck gas and run unless the vacum in the crankcase gets weak

​don't give up on it !