1985 90HP Inline 6 CYL - Final Update - Carburetor Help!

[ZigZaggin]

Serial number 6623492

Ok - so long story short had an issue with the bottom brass plug under the main nozzle while rebuilding carbs and cracked the carburetor casting! Carburetor is a WMK-39 (center carb). I've called around and have found WMK-24, WMK-25, and a WMK-41 (WMK-41 is for 115 i believe). I would really rather just match it up with the other two but i guess in this situation beggers can't be choosers. If someone can tell me where I might be able to find a WMK-39 (center or bottom carb only) I would be truly greatful. Also, if someone has expertise and can tell me what other carbs will work for replacement that would be very valuable as well. Thanks in advance for your time and knowledge!

-zig

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

bump

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

So here's to responding to my own post... Called my mechanic friend and he had a WM-23 carb on the shelf. I decided to try it since he didn't charge me for it and saw on the rebuild kits that this carb was included in the same group of models as the WMK-39.

Put in the .074 main jet and used the bowl cover from the cracked WMK-39 (bowl cover not damaged). The motor did fire right up and run however it didn't quite seem right. Didn't idle right. These carbs don't have a choke, only the enrichener so I covered the front of the carbs with my palm to see if they were pulling air and if my hand got fuel on it. I figured this was at least a decent way to tell if they were delivering fuel and air was moving. Interestingly, the center carb (the WM-23) had noticeably less suction than the top and bottom.

Just fixed spark issue on #4 cylinder by replacing a coil. It's likely that cylinder ran without spark for a month or 2 (maybe 6-8 hrs run time). In the meantime I plan on swapping the WM-23 down to the bottom to see if the suction issue follows it and also do a compression check. Will continue to look for better match WMK-39 or WMK-35. If anyone has one or knows where I could get one that would be great!

thanks,
-zig

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Update... My mechanic friend just couldn't accept the fact that the motor wouldn't run right because of that carb. Truth is I really didn't need to rebuild the carbs anyway. I am a bit of perfectionist and didn't like the way they looked due to the years of fuel build up. Fact of the matter is, unless you let the engine run the carbs out of fuel when you tilt for trailering fuel is going to pour out of them :/

So anyway... Here's the fix. We pulled the center problematic carb (WM-23) and took all the brass plugs and the welch plug out. Then he grabbed a piece of 14 guage guitar string. Very, very thin yet stiff. Lonni (mechanic) surgically worked the guitar string through every little nook and cranny (even the tiny tubes you can only see with the brass plugs removed) of that carb and used about half a can of gumout on it and a lot of compressed air. Put a new welch plug in... He tapped it in with the handle off a small, broken wooden spoon and then sealed it with a material called Gasoila (red varnish looking). We hooked it all back up and wow, what a difference! That motor idles very smoothly now!

He adjusted the idle as follows... He screwed the idle mixture screws all the way in and did this very lightly. He said you never want to seat them very tight. Then he backed each one out 1.5 turns and fine tuned from there. He has an ear for these motors and honestly, at times I didnt think he was even turning the screw. Anyway, when it comes to carbs and cleaning get serious and downright anal about it. It pays off. We double checked the compression and it was all great. Now I just gotta find the Walleyes!

Hopefully someone will find this useful.

-zig

 

[Bob_VT]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

You want perfection? Read this link http://forums.iboats.com/showthread.php?t=168855

That is the magic formula for the inline towers

 

[arsenalpsu]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

AND if you for what ever reason do need some parts for this engine PM me and I can give you the contact info for the person who created that thred- he know's his inlines.

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Many, many thanks to arsenalpsu. Through his contacts I got a full set of WMK-39's for $75 delivered. Couldn't be happier.

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Oh and for the record, the "suction" issue on the middle WM23 carb was due to #4 cylinder not firing... again! #4 coil was replaced less than a week ago. Now I have a bad switchbox that's not firing the #4 hole too! What a coincidence. Coil checked out. Replacing both switchboxes with CDI so hopefully they last.

 

[achris]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

I'm wondering if the bad coil had anything to do with the switchbox failure... I used the Merc boxes for years without a problem...

0.02

Chris.......

 

[ZigZaggin]

Re: 1985 90HP Inline 6 CYL - Final Update

Re: 1985 90HP Inline 6 CYL - Final Update

First off I need to corect the info I've posted about the WMK-23 (WM-23) carburetor used as a replacement when I dropped and cracked the original middle WMK-39 carb (Bad Day). Local shop told me it would work. After the #4 coil and 2 new CDI switchboxes the motor would run perfect on the first run at WOT. This started on Sunday, March 21st (First Walleye Tournament). I took it out again after that and the exact same thing happened. Ran great to first spot but then after fishing for a while and heading to another spot she would bog down and I would only get 4000 rpm.

Follwing Tom's advice to not run the motor much above idle when it was doing that I decided to call him even though it was Saturday. As luck would have it he was heading to his shop which was very close to where we were fishing. This was my first time out since the tournament. What I love about the guy is his dedication to a problem. He met us at the ramp with a timing light and DVA meter and hopped in the boat. Everything in the ignition system checked out so with the cowl off and running at WOT he individually put his hand over each of the the three carbs. The engine stumbled a couple of times... Then he had me back it down to an idle. He put his hand over the middle (WM-23) carb and told to slam the throttle. There was a definite imporovement and you could hear it. The boat would not run right at WOT unless his hand was over the middle carb. Even when I pushed the key in to run the enrichener it didn't help. He said that carb was not supplying enough fuel at WOT and had less suction than the other 2. The boat picked up about 400 RPM that way but wasn't 100%. Because the carb had to be "hand choked" it would never get enough air but did supply more fuel that way. He said most likely it had a restriction and to never run lean! Either that or the bore was different but that didn't explain why it would run great to the first spot so he was sure it was restriction. Anyway, he said I better get the right carb and not run the motor again until I had it on there.

Striking out locally and at a couple of online used marine parts sites I reached out to the forum. With the help of some really great people on this forum I was directed to a guy in Seattle who is an inline enthusiast and had a whole set of WMK-39's. He had em to me in 3 days. They were complete and exact matches. I cleaned the middle carb in the set, put a rebuild kit in it just to be thorough, and installed it. Ever since then the motor has been unstoppable and great.

I got a stainless 18 pitch mercury vengeance prop on ebay for $115 (brand new) and a hub kit for $30. Tops out about 42 mph downstream on the Mississippi and about 35 mph upstream at 4800 rpm. I know they say not to run these inlines below 5000 but I figured that was close enough? With a 17 pitch aluminum I was running 5300 so the 500 rpm drop on a 1" pitch change doesn't seem quite right. I guess stainless is less flexible and harder for the motor to turn?

Thanks again to everyone on this forum. Definitely a valued resource. Hopefully my story helps.

 

[achris]

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Re: 1985 90HP Inline 6 CYL - Carburetor Help!

Thanks for the update... Nice to hear that you're all sorted... I bet you learned a lot.