'05 merc 50hp fuel and impeller questions

[dpeslinger]

Hi all.
I just got the above mentioned engine on a tracker pontoon. the seller told me the fuel line check valve in the interior tank was bad so he ran a external 5 gal tank. i have looked and cant find any "check valve" in the tank. I have looked and there is not check valve inside the tank. Is not the primer bulb the valve?
He told me also the Impellor works good but the engine is not peeing. i took off the LU and the impellor looks ok. I put a water hose to the inlet valve on the bottom of the power head and i get water flow out the telltale. re assembled and no water comes out. I did notice one of the washers between the impellor and the housing is missing. will that cause this? thx.

 

[Texasmark]

Re: '05 merc 50hp fuel and impeller questions

There is no washer inside the housing. The impeller seals against the cover and bottom plate of the water pump which is the same hole pattern as the cover.

Usually there is nothing in the tank but a screen of varying types. Yes the squeeze bulb has a check valve. Was he eluding to a fuel supply problem? Since you ran the engine I guess you don't have one.

Where is your pee hose connected? Most I've seen are plumbed straight over to the exhaust manifold exhaust water jacket cover on the Port side of the engine. My '02 90 is plumbed that way. However on larger V engines I have seen it plumbed off the stat and the stat has to open before you get any.

Course you said you got water through the pee hose using your garden hose, but your hose pressure runs about 70psi give or take and the pop off adjacent to the thermostat pops off at about 2500 rpm which amounts to about 5 or so psi. So the popoff could bypass the stat and let water out if plumbed off the stat. If so, the hose will be attached to the cover plate for the stat and popoff.

I'd pop the cap off that covers the stat and popoff (on the water jacket cover usually above and to the left of the spark plugs). Pull the stat and popoff and run the engine just long enough to verify that the block is filling with water and it is flowing out those holes in reasonable volume. If no water something is wrong with your water delivery system.....copper tube not inserted correctly, water leaking from the interface of it to the block or pump due to a seal missing. When finished with your testing ensure that you put them back.

HTH,
Mark

 

[dpeslinger]

Re: '05 merc 50hp fuel and impeller questions

@ texasmark... Sir with respect you are wrong. the impellor has a thrust washer above and below the impellor. looks like a plastic washer.

ANYONE????? if one of these washers is missing will this prevent the impellor from pumping water?

 

[Texasmark]

Re: '05 merc 50hp fuel and impeller questions

Ok then yours and my 90 are different. My manual and the water pump I just dismantled less than a month ago to install a new impeller doesn't show/doesn't have anything in there but an impeller and a drive shaft locking key. What it did have were score marks on the cover and plate where the old impeller had scored the SS but not so bad as to require replacement.

So sir, I have a question or two for you. If the job of the impeller is to suck in water, pressurize it and pump it out, how does it do that with a spacer washer between the rubber impeller and the housing where you need a sealing surface?

Where is there anything developing thrust and enough thrust at that to require a dedicated washer to support it?

How do you develop a suction and how do you develop pressure if the water can bypass the blades via a "thrust" washer?

Why is it that periodically you have to buy a whole new water pump assembly when the turning rubber seals of the impeller score the inside of the pump cover or lower plate to the point where some of the suction and pressure are lost via bypass?

The question of how deep do the groves need to be before replacing the whole pump was asked on here not too long ago.

What you do have is a seal on the output tube to the engine block, and under the pump base around the drive shaft you have:

A gasket that conforms to the shape of the bottom of the housing,

an upper and lower drive shaft seal for keeping water out of the lower unit oil,

a 2 part carrier assembly,

and a wear sleeve assembly all at the upper part of the lower unit and at the lower end of the drive shaft,

some shims for setting the pinion to FR gear spacing below where the prop shaft interfaces,

a bearing and race to support the lower end of the drive shaft, a pinion gear and locking nut.

There are no "thrust" washers in the whole shebang. Any thrust in the "circuit" is handled by the pinion bearing against the pressure of the pinion gear nut.

But I'm just trying to help you get your problem solved. My impeller is already installed and working fine. They sell Seloc manuals on here and you don't even have to buy the whole thing. You can just subscribe for a period of time and view what you want online. I do that and have my Merc manual. Seloc is very definitive and lots of pictures.

HTH,
Mark

 

[Fun Times]

Re: '05 merc 50hp fuel and impeller questions

I believe he's talking about item numbers 15 & 17,
http://www.mercruiserparts.com/Show...c=Gear+Housing(Driveshaft)(1.83:1+Gear+Ratio)

Interesting enough, part #12-86645 1 is no longer available from mercury outboard parts, but can be found with a google search if desired.

Found in the mercury service manual,

Washer (above impeller), Washer (below impeller)

NOTE: Replace cover if thickness of steel at discharge
slots is 0.060 in. (1.524mm) or less, or if
groove(s)(other than impeller sealing groove) in cover
roof are more than 0.030 in. (0.762mm) deep.

NOTE: If water tube seal remained in drive shaft
housing, remove seal from housing and reinstall on
water pump cover. Secure seal to cover with Loctite
405.

 

[Texasmark]

Re: '05 merc 50hp fuel and impeller questions

I believe he's talking about item numbers 15 & 17,
http://www.mercruiserparts.com/Show...c=Gear+Housing(Driveshaft)(1.83:1+Gear+Ratio)

Interesting enough, part #12-86645 1 is no longer available from mercury outboard parts, but can be found with a google search if desired.

Found in the mercury service manual,

Washer (above impeller), Washer (below impeller)

NOTE: Replace cover if thickness of steel at discharge
slots is 0.060 in. (1.524mm) or less, or if
groove(s)(other than impeller sealing groove) in cover
roof are more than 0.030 in. (0.762mm) deep.

NOTE: If water tube seal remained in drive shaft
housing, remove seal from housing and reinstall on
water pump cover. Secure seal to cover with Loctite
405.

Okaye that's what an I/O uses. He has a 50 hp outboard. I haven't been into a Mercruiser for 40 years and I don't remember what the water pump shape is. What I said about pumping capability holds for all of them so apparently the housing and plate are modified, or the impeller itself is modified to support the installation of the seals.

Back to my initial point: If the SM specifies the allowable limits on the wearing of the pump housing and plate then it is for the reason I mentioned. So if they are that sensitive, how can you justify putting a washer or what have you in there between the rubber sealing surface of the impeller and the housing? Beats me unless the housing is offset to accommodate the difference.

Where's Laddies. He knows about all this stuff!!!!!!!!

Mark

 

[Silvertip]

Re: '05 merc 50hp fuel and impeller questions

The technical term for the check valve being referenced is the anti-siphon valve. It is not located IN the tank but is a screw in fitting at the outlet of built-in fuel tanks. This valve prevents siphoning of fuel if there is a fuel leak in the fuel hose between this fitting and the engine. It is commonly thought it's purpose is to prevent fuel flow back to the tank but that's not the case.

And looking at an impeller is not a check of it's ability to pump water. Good looking impellers can be complete junk. As for impellers using washers or not, that depends on the design of the housing and the impeller itself. Impellers need to seal on top, bottom and ends. If the impeller fins are the same width from hub to tip, then a washer will prevent the top and bottom from sealing. It's all about design. If the pump needs washers, install them. Otherwise not.

 

[Fun Times]

Re: '05 merc 50hp fuel and impeller questions

Okaye that's what an I/O uses. He has a 50 hp outboard.

To be clear on the subject, The parts catalog links above & below are for his 50 hp outboard.
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=803026001

Also pages 6A-4 & 6A-11 of his service manual will show the 2 washers in question.

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/852572r1/6a.pdf

 

[Texasmark]

Re: '05 merc 50hp fuel and impeller questions

To be clear on the subject, The parts catalog links above & below are for his 50 hp outboard.
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=803026001

Also pages 6A-4 & 6A-11 of his service manual will show the 2 washers in question.

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/852572r1/6a.pdf

Thanks.

Now he knows for sure what the requirements are and I see another example of where OEM's change things in different hp ranges for whatever reason. I guess that's why I reference my comments as to where my information originates. Not that it means anything to the recipient, but at least he knows that I am talking from a different engine and differences can and will exist.

Mark

 

[dpeslinger]

Re: '05 merc 50hp fuel and impeller questions

Fixed the impellor thanls all for replies. now to the aniti siphon valve

 

[Fun Times]

Re: '05 merc 50hp fuel and impeller questions

What was wrong?

 

[dpeslinger]

Re: '05 merc 50hp fuel and impeller questions

What was wrong?

replaced impeller,