1958 18 HP Fastwin

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Jul 8, 2009
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I currently have a 18 HP Fastwin on a 14 ft Sea Nymph aluminum boat. I have read several forams and similiar setups, they are getting between 22 and 26 MPH. I am getting between 11 and 15 MPH. I have tried adjusting the trim, nothing seems to get me any more power. Anyone know anything about these old motors and what might be causing the power loss?
 

kbait

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Re: 1958 18 HP Fastwin

If it's only firing on one cylinder, it'd do that, and seem smooth.
 

kfa4303

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Re: 1958 18 HP Fastwin

I agree. check to make sure that both cylinders are firing properly. I'm thinking that you are running on just one cylinder. You may have a bad coil and/or points/condensers. it's amazing how well these things can run on just one cylinder. you should get approx 25mph as you said, but because you're only getting about 1/2 that I'm suspecting on cylinder isn;t firing. No worries. It's easy enough to fix. Pull the fly wheel and let us know what you find. If the coils are cracked then they're bad, if they're ok then look at the points and condensers. you may as well change them while you have the flywhell off. You can get them here at iboats as a "Tune up kit" about $20 and worth every penny. Check your spark then let us know what you find. We can walk you through anything you may find.
 
Joined
Jul 8, 2009
Messages
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Re: 1958 18 HP Fastwin

Thanks for the info, I will pull the fly wheel tomorrow. I have not done any boat motor repair before, but will let you know how it goes. If the coils are bad, do you sell them at iboat as well?
 

1946Zephyr

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Oct 21, 2008
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5,556
Re: 1958 18 HP Fastwin

Well, fortunately, the old 18's are easy to work on and very reliable. So you picked out a great motor.
 
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Re: 1958 18 HP Fastwin

Well I finally got around to working on the motor. I pulled the flywheel and both coils are black hard plastic (not the maroon or red that originally came on these motors) and have no visible cracks. The condensers look fine as well. I have spark from both plugs so I had the compression checked and I am over 100 PSI in each cylinder. I am perplexed. While the guy checked the compression I had him fire it up and run it. In the test tank he said it sounds like it is only running on one cylinder when under load. He seemed to think it needed a whole new electrical rebuild.

I am not sure when the last time the carb was cleaned, could I have a clogged jet or something that would reduce the power or block one of the cylinders or do you agree that the coils, condensers etc be rebuilt. He did also notice that the plug wires were old and probably original and that they are solid core wires that sometimes break.

Help!!!
 

HighTrim

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Jun 21, 2007
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10,486
Re: 1958 18 HP Fastwin

When you say you had spark checked, how did you do it? If you held the plug to the block, that is not a suitable test.

In situations like this, I like bringing my inducting timing light while I run the motor on the lake to watch the spark. Bare minimum you need to use an inline open gap spark tester set to 3/8". Spark should jump the gap with a bright blue ZAP!!

If the wires look bad, get your meter out and test the continuity.

Let us know what you find.
 

kfa4303

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Re: 1958 18 HP Fastwin

The good news is that a "whole new electrical rebuild" really only includes coils, points, condensers, and sparkplug wires and sparkplugs. Sounds like the coils are fine so it wouldn't cost more than $50 at most. Points and condensers (tune up kit) is approx. $20, copper core s'plug wire are about $2 a foot, s'plugs are about $5 each and that's really all you need. You should probalbly rebuild the carb too. You can get a rebuild kit for about $20 too. There are tons of links here that can walk you through how to replace/rebuild all the bits you need. It sounds like a lot, but it's really well worth it and kind of fun to do. You'll learn a lot too. Good luck.
 

backyard mechanic

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Jan 6, 2009
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Re: 1958 18 HP Fastwin

STOP! Do yourself a favor and check compression. There is no sense in buying lots of parts if the motor is toast. Learn how to read and understand compression testing. There is a "story" told every time you turn the engine over... Learning what is said is going to help you buy the RIGHT parts.
 

kbait

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Re: 1958 18 HP Fastwin

Check spark w/a tester to ensure a 1/4" blue bolt in open air. It needs to have that in order to fire the plug's gap .030" under compression. If it's good, change the plugs. If it's yellow or weak, Remove points file clean/shiny and reset to .020" and test again. If one is still yellow/weak, replace that condenser. If it's still bad, scrutinize connections from plug wire to boot, and plugwire to coil.
Sidenote: W/plugs in, pull the recoil rope rather slowly, if you feel a strong 'whump-whump' and it's even between both whumps, you have good compression on both cylinders. If one is definitely weaker, check head gasket.
 
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Jul 8, 2009
Messages
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Re: 1958 18 HP Fastwin

OK, this is the latest update on my motor:

compression is over 100 psi per cylinder.
I did a spark test, was only getting a spark at 1/8 inch. I cleaned the points, reset at .020(they were not even close to being set at that) and now I get a good blue spark at 1/4 inch.

I just took it out for a test run, and I have gone from 11 - 15 MPH to a solid 17.5 MPH with just myself in the boat.

However I cannot get my low idle to do anything, when I throtl back to slow, it sputters and skips until it stalls out or I give it more gas. I am thinking I now have a carb problem.

with the spark OK, and compression good, can you think of anything else except the carb. not sure when the last time it was cleaned (not since the last 3 years that I have owned it).
 
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Re: 1958 18 HP Fastwin

Gentlemen, I have been doing some additional research. You guys have been great and I would like to know if you can verify one more thing for me? After checking everything listed above and countless hrs of trying to figure out what is wrong, I think I might have been misinformed.

The SN on the Fastwin is 15016 14285. From what I have read, the 15 indicates a 15 HP??? This would probably explain why I am not getting the speed that I am expecting out of an 18 HP.

When I bought it I was told it was an 18 hp Fastwin, and did not bother to research the HP of the motor.

If this is a 15, I have wasted a lot of time and will have to be satisfied with 17 MPH until I upgrade to a different motor.
 

AlTn

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Re: 1958 18 HP Fastwin

Googlin' around...Evinrude 15016 comes up with a 1956 15 hp...on the bright side, at least you know what you have and can order parts
 

kfa4303

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Re: 1958 18 HP Fastwin

I believe they used the same powerhead and other components on the 15 and 18 of this era. I believe the only real difference between them was the carb. While 3hp isn't a lot it can make a difference with small boats. I would still clean/rebuild the carb and dial in the hi/lo speed needles along with the idle set screw found at the base of the vertical throtle tower. It may take some figgling, but once you have them all set you shouldn't have to mess with them again. Glad you got her running again. Glad you got her running again.
 
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Re: 1958 18 HP Fastwin

after playing with the carb, engine still runs rough (sounds like it skipping or hickupping)

replaced plugs, condensers and points, ran great for about 30 seconds, pered right along at low idel, then started sputtering and skipping again.

Back to thinking I need to replace coils?
 

kfa4303

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Re: 1958 18 HP Fastwin

Sounds more like a "lean sneeze" to me. A much easier fix. Try backing out the lo speed needle about 1/8 or a turn and see if that helps. Once you've got the idle set be sure you tighten down the brass packing nut on the hi/lo needles once the idle is set, so they don't move due to the vibrations of the motor as it runs. Here's a link that can walk you through dialing in your carb. Stick with it. Your almost there and once they're set you won't have to worry about them again. Good luck. Keep us posted.


http://forums.iboats.com/showthread.php?t=167352


http://forums.iboats.com/showthread.php?t=167352
 
Joined
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Messages
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Re: 1958 18 HP Fastwin

Well that was it. I backed out the low idle and tweaked it. I will hopefully be able to take it back out of the test barrel and for a test run this week. It idles great. You guys have been awesome helping me solve my issues.

after all is said and done, I replaced the points and condensers, cleaned the carb, and discovered my 18 HP fastwin is actually a 15 hp fastwin and I am probably maxing out at 17 MPH. Oh well it runs nice now.

Thanks!!
 

kfa4303

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Re: 1958 18 HP Fastwin

Congrats. You may be able to squeeze a few mph out of her by removing/rearranging some weigh in the boat, but 17-20 mph from a 15hp motor on a 14ft. boat is about right. Glad she's running good now.
 
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