Fuel System O rings

dougd1

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I have a Merc 9.9 o/b 4 stroke engine. The carb on this particular motor has a priming bulb and hose that attaches to the bottom of the carb. If you remove the cover where the hose attaches there are two small o-rings inside. Does anyone know the size or part number for these o-rings? They are likely metric o-rings. I am trying to find replacement ones, but I don't know their size or OEM part number. SN of the motor is OR126144. Any help appreciated. Thanks.

Doug
 

dingbat

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I have a Merc 9.9 o/b 4 stroke engine. The carb on this particular motor has a priming bulb and hose that attaches to the bottom of the carb. If you remove the cover where the hose attaches there are two small o-rings inside. Does anyone know the size or part number for these o-rings? They are likely metric o-rings. I am trying to find replacement ones, but I don't know their size or OEM part number. SN of the motor is OR126144. Any help appreciated. Thanks.

Doug
O-rings have a standardized (AS568) numbering system

Measure the diameter of the cord and OD of the oring and use lookup table to find the part number.

 

dougd1

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O-rings have a standardized (AS568) numbering system

Measure the diameter of the cord and OD of the oring and use lookup table to find the part number.

The old o-rings were quite deformed like flattened donuts so any measurement of those would not give me the correct reading. My o-rings are likely metric. The chart you pointed me to are US sizes, simply converted to metric, so am not convinced the chart would work for me.
 

dougd1

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Have you had a chance to search over your engine model parts diagram to see you could locate them?

Thinking either it’s in here,

Or here, https://www.mercruiserparts.com/bam/subassembly/28341/10750/90

And if not here’s your complete parts catalog, https://www.mercruiserparts.com/8-4-stroke-209cc-0p325500-up
My carb seems to have a different configuration from these parts diagrams. These diagrams I think show a later model of the carb that did not have a priming line and bulb hooked up to the carb.
 

Fun Times

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My carb seems to have a different configuration from these parts diagrams. These diagrams I think show a later model of the carb that did not have a priming line and bulb hooked up to the carb.
Maybe try posting a few photos of what you’re describing to see if it may help any…

Maybe @Yegboats will have some insight too.
 

dougd1

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Maybe try posting a few photos of what you’re describing to see if it may help any…

Maybe @Yegboats will have some insight too.
Here are a couple of photos - I did hear back from Mercury -the part I am looking for is 898103224, which shows up on the diagrams you posted. However, I cannot find the configuration of my carb that has the priming bulb and hose configuration. Is there any way to find out the size of these o-rings given the Merc part number?
In the photos, you can see the priming hose entering the bottom of the carb. The plate it attaches to comes of with a couple of small screws/bolts, the o-rings sit in a couple of recesses in the plate.
 

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dingbat

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The chart you pointed me to are US sizes, simply converted to metric, so am not convinced the chart would work for me.
ISO cross-sectional diameters differ from the Aerospace Standard (AS568) by less than 0.001 inch. Many/most AS568B sizes are interchangeable with an ISO size. ;)

O-rings can and do distort overtime but your o-rings are obviously still in good enough condition to make an educated guess.

What is the cross section of the cord and OD of the o-rings as installed?

Fluent in both "metric" or "imperial" units
 

dougd1

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ISO cross-sectional diameters differ from the Aerospace Standard (AS568) by less than 0.001 inch. Many/most AS568B sizes are interchangeable with an ISO size. ;)

O-rings can and do distort overtime but your o-rings are obviously still in good enough condition to make an educated guess.

What is the cross section of the cord and OD of the o-rings as installed?

Fluent in both "metric" or "imperial" units
Unfortunately, my o-rings now look like discs with a hole in the center. They have completely lost their circular cross section. For what is worth, disc diameter is 0.317" (7.98 mm), hole diameter is 0.141" (3.53 mm) and disc thickness is 0.053" (1.35 mm). I do not have the "as installed" measurements. That is what I am trying to find out so I can source something. Local dealer does not have any of these o-rings in stock.
 

Fun Times

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Can’t directly help with finding the exact measurements though sometimes you can search the part numbers and see what they may look like against a ruler placed next to them for maybe a general idea.
Here’s a few to look over in your search’s,

1653527372071.jpeg

Also the equivalent part number to the Merc number above is 3BJ032430 by Nissan / Tohatsu Marine,
1653528125041.jpeg
 

dingbat

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For what is worth, disc diameter is 0.317" (7.98 mm), hole diameter is 0.141" (3.53 mm) and disc thickness is 0.053" (1.35 mm). I do not have the "as installed" measurements.
You may want to check your measurement conversions on the "disk" and "hole" dimensions.....

Your ID and OD measurements don't add up to any available cross section.

(OD - ID)/2 = CS

Reported = 0.317 (8.1) x 0.141 (3.6) x 0.089 (2.2)*

Available Sizes:
105 = 0.343 (8.7) x 0.143 (3.6) x 0.103 (2.6)*
2.1 x 3.5 = 0.335 (8.5) x 0.137 (3.5) x 0.098 (2.5)*
2.2 x 4 = 0.330 (8.4) x 0.157 (4.0) x 0.087 (2.2)*
*calculated based on ID and OD measurements

With suspect measurements and not knowing if its a gland or radial seal, my first choice would be the AS568-105 based on availability although the 2.1 x 3.5 ring appears to match up better from your measurements.

Ideally, you want to measure the ID, OD and depth of the o-ring groove itself. On radial seals, measure OD of tube and ID of the housing to get a definitive answer to the question
 

Yegboats

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Maybe try posting a few photos of what you’re describing to see if it may help any…

Maybe @Yegboats will have some insight too.
Sorry I'm a few days late. I like dealing with the parts thingies
There are 2 serial ranges of carburetors listed on the parts schematic when you punch in your serial number
0r676745 and below (correct one)
0r676746 and up If you chose this one you will only see 1 option for
Your serial number is

ENG: 0R126144 1F10201FK MERCURY 9.9 M 4 "2006"
M The M 4 after the 9.9 stand for Manual start, short shaft (15”/381mm) driveshaft housing. Tiller handle steering
@Fun Times has give you the part numbers for #44
When I look at the epc, and your carb they look the same to me. I highlighted the parts that look the same. #29 is for Tiller steering units I'm assuming maybe the wrong one was selected?
 

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dougd1

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Sorry I'm a few days late. I like dealing with the parts thingies
There are 2 serial ranges of carburetors listed on the parts schematic when you punch in your serial number
0r676745 and below (correct one)
0r676746 and up If you chose this one you will only see 1 option for
Your serial number is

ENG: 0R126144 1F10201FK MERCURY 9.9 M 4 "2006"
M The M 4 after the 9.9 stand for Manual start, short shaft (15”/381mm) driveshaft housing. Tiller handle steering
@Fun Times has give you the part numbers for #44
When I look at the epc, and your carb they look the same to me. I highlighted the parts that look the same. #29 is for Tiller steering units I'm assuming maybe the wrong one was selected?
I heard back from Mercury - the part number for the carb I have appears to be 8M0176126, but I cannot find a schematic on their on-line parts catalog. They said the carb has been superceded several times over the years. Parts 44 and 29 you took from the schematics of the carbs from their on-line parts catalog have the same part number (898103224) which is the number Mercury provided to me. They declined to provide the dimensions/specifications of the o-ring unfortunately.
 

dougd1

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You may want to check your measurement conversions on the "disk" and "hole" dimensions.....

Your ID and OD measurements don't add up to any available cross section.

(OD - ID)/2 = CS

Reported = 0.317 (8.1) x 0.141 (3.6) x 0.089 (2.2)*

Available Sizes:
105 = 0.343 (8.7) x 0.143 (3.6) x 0.103 (2.6)*
2.1 x 3.5 = 0.335 (8.5) x 0.137 (3.5) x 0.098 (2.5)*
2.2 x 4 = 0.330 (8.4) x 0.157 (4.0) x 0.087 (2.2)*
*calculated based on ID and OD measurements

With suspect measurements and not knowing if its a gland or radial seal, my first choice would be the AS568-105 based on availability although the 2.1 x 3.5 ring appears to match up better from your measurements.

Ideally, you want to measure the ID, OD and depth of the o-ring groove itself. On radial seals, measure OD of tube and ID of the housing to get a definitive answer to the question
The measurements I took of the old o-rings are correct. The problem is - the o-ring no longer looks like an o-ring. I assume over time it lost its elasticity and torus shape and became disc-shaped. The thickness of the disc actually equates to the distance between the bottom plate on the carb and the carb body.
I calculated the cross section of my disc and assuming it represents the cross-section of a torus, I end up with the diameter of cross section of the torus being 0.073" or 1.856 mm. That assumes the disc had a perfectly rectangular cross-section (which it doesn't), the most likely diameter of the original o-ring cross section is either 1/16" or 1.70 mm. I would simply have to pick an o-ring with an appropriate OD. The application is a radial seal.
 

Yegboats

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518
The measurements I took of the old o-rings are correct. The problem is - the o-ring no longer looks like an o-ring. I assume over time it lost its elasticity and torus shape and became disc-shaped. The thickness of the disc actually equates to the distance between the bottom plate on the carb and the carb body.
I calculated the cross section of my disc and assuming it represents the cross-section of a torus, I end up with the diameter of cross section of the torus being 0.073" or 1.856 mm. That assumes the disc had a perfectly rectangular cross-section (which it doesn't), the most likely diameter of the original o-ring cross section is either 1/16" or 1.70 mm. I would simply have to pick an o-ring with an appropriate OD. The application is a radial seal.
Are you doing all this to save 14 bucks cdn by not ordering the tohatsu,or merc o-rings? I get it they're expensive for a wee oring but simetimes you got to suck it up and clear up the headspace.
Youre gonna flip next time you change gear lube and have to pay almost 9.00 cdn each for the drainscrew washers.
 

jimmbo

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I remember people flipping when they were $1.25 each. Hmm, I could have adjusted the price, just for them to $2.50/ea
 

dougd1

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Are you doing all this to save 14 bucks cdn by not ordering the tohatsu,or merc o-rings? I get it they're expensive for a wee oring but simetimes you got to suck it up and clear up the headspace.
Youre gonna flip next time you change gear lube and have to pay almost 9.00 cdn each for the drainscrew washers.
Nope, just would like to know the size. Have taken the motor into a merc dealer to clean the carb and generally check out the engine. Lots of minor issues that I hope he can clear up, most of them associated with the carb. Pricing is weird though - spent $38 on a liter of gear oil for the lower unit last fall - same oil and brand at Cdn Tire this spring - $20.
 

Yegboats

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Messages
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Nope, just would like to know the size. Have taken the motor into a merc dealer to clean the carb and generally check out the engine. Lots of minor issues that I hope he can clear up, most of them associated with the carb. Pricing is weird though - spent $38 on a liter of gear oil for the lower unit last fall - same oil and brand at Cdn Tire this spring - $20.
The canadian retail for quicksilver premium gearlube is about 25.00 now. I think high perf is around 33.00
Just 1 year ago it was 16.00 and 22.00
Canadian tire gets big volume discounts on their oil from Mercury. Unfortunately your average dealer dont get these volume discounts.
At my dealership they have spent 10s of thousand of dollars in training their staff. Not to mention the pay differences between Canadian tire and a dealership.
I would expect the dealers to be more expensive than Canadian tire but if you paid 38.00 at your dealer last fall for premium, thats excessive.
 
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