Engine fire

Destroyer · #1 07-20-2010, 12:44 AM

Well, I found out what the problem was with my engine. Seems I had a little fire. Number 6 cylinder must have blown back out the reed block because that's the one that the carb body is badly burned. Number 5 is also burned slightly, but will be replaced. What IDIOT decided to make carb bodies out of plastic????? You can put out a fire on a metal body, clean thngs up and motor home. Plastic burns for Gods sake.. what the heck were they thinking??

The number six was so badly burned that the idle and intermediate jets were clogged with melted plastic...so of course it wasn't running right.

Anyways two new (used) carbs are on their way to me. Meanwhile I've removed the butterfly plates and mounting plate behind it. A visual inspection of the reeds looks like they are ok, but I'll remove the reed blocks tomorrow and clean and check them to make sure the petals are all ok. fun fun fun..

Skools Out · #2 07-20-2010, 06:06 AM

um i noticed you have your motor listed as 200 hp but that's a 225 motor. those are 225 carbs which makes your motor a 225. hope you bought the right carb bodies.

Destroyer · #3 07-20-2010, 07:45 AM

Quote:

Originally Posted by Skools Out

um i noticed you have your motor listed as 200 hp but that's a 225 motor. those are 225 carbs which makes your motor a 225. hope you bought the right carb bodies.

LOL.... Skools, I'd love it to be a 225, but alas, it's only a 200. Those are Type IV carbs, used on 200 and 225 V6's from 1986 forward and on 120 and 140 V4's from 1985 forward, according to my service manual. In all cases, I contacted the company that did the original rebuild of the motor, they looked up the serial number in their records and are the ones sending me the carbs.

It still doesn't explain how anyone could be so dumb as to make a carb body out of plastic. Talk about a fire hazzard! I'm ready to pull the engine and strap my 200 Merc on.

Blue_Runner · #4 07-20-2010, 08:44 AM

Good work Destroyer!

Skools Out · #5 07-20-2010, 10:36 AM

hate to tell ya but the 200 carbs were not the same those are 225 carbs. the 225 carbs have 3 screws in the butterflies and 200 carbs have 2 screws. unless your motor is an XP model which was actually a 225 in 200 skin.

Skools Out · #6 07-20-2010, 11:14 AM

these are 200 carbs.

these are the 225 carbs

notice how much larger the throats are on the 225 carbs they are hugh compared to the 200's

Destroyer · #7 07-20-2010, 03:47 PM

Quote:

Originally Posted by Skools Out

these are 200 carbs. These are the 225 carbs. Notice how much larger the throats are on the 225 carbs they are huge compared to the 200's

Skools, when you're hot you're hot. I stand corrected on the carbs. It's wierd that the service manual makes no mention of the different size of the venturi. Thanks for pointing it out... I learned something today :) Since this is a rebuilt/repainted motor I have no way of knowing what it started out as. Unfortunately all there is is a serial number, no model number. I've always gone by the cowling that says Johnson 200 on it as you can see in my avatar pic. It may very well be an XP. I do know that she's got a ton of power...scary actually. Like I said, the people that rebuilt the motor are sending me the carb bodies.... lets see what they send me based on their records.

THEFERMANATOR · #8 07-20-2010, 10:16 PM

Definately 225 carbs. Also make sure that you get the right ones and swap ALL of the jets INCLUDING the brass pick-up tubes inside of the bowls. OMC made ALOT of changes to the pick-up tubes from year to year, and even sometimes had 3 different variations in the same year. I would also pull the intake off and replace the reeds. If it backfired hard enough to pop out the carbs, then the reeds will have micro cracks in them from it. And when a metal reed breaks, it will go through the engine and either knock a hole in the block in the rod slot(best case scenario), OR it will destroy a piston and sleeve and could even push the sleeve through the head.

Destroyer · #9 07-21-2010, 02:56 PM

Quote:

Originally Posted by THEFERMANATOR

Definately 225 carbs. Also make sure that you get the right ones and swap ALL of the jets INCLUDING the brass pick-up tubes inside of the bowls. OMC made ALOT of changes to the pick-up tubes from year to year, and even sometimes had 3 different variations in the same year. I would also pull the intake off and replace the reeds. If it backfired hard enough to pop out the carbs, then the reeds will have micro cracks in them from it. And when a metal reed breaks, it will go through the engine and either knock a hole in the block in the rod slot(best case scenario), OR it will destroy a piston and sleeve and could even push the sleeve through the head.

Fermanator, I already have the reed blocks off and cleaned. To my machinist practiced eye they look ok. There's about a .005 - .010 gap between the petals and the base on all of them, and that's what the book says is ok, but I've have already made the decision to replace them. I don't want to take this engine apart a second time, so am going to take my time and make sure the front end is all ok before I put the engine back in service. Good call about the 2 brass pick up tubes inside of the bowls.. I didn't know that OMC made different sizes...(although it doesn't surprise me). I'll make sure they are the same and if not I'll change them out. Do they pull out or are they screwed in? I've already cleaned all the servicable carbs and carefully pulled and ID'ed the idle, intermediate and high speed jets from the other two carbs so I can put them into the new bodies when they arrive. All passages have been cleaned and blown out with compressed air in all the bodies and the butterfly plates behind them. Anything else I should be looking out for? Thanks for all the help guys... most appreciated!!!

nymack66 · #10 07-21-2010, 03:32 PM

Check both the throttle bodies and the replacement carbs if any warped with all that heat from the fire ?
Also I think you have six petals reeds ? If yes I have OEM spares ..let me know ...