Grant MacLaren's
1981 18' Century Resorter

Fuel Pump
(Click on any image for a larger version.)
In a message dated 9/30/2011 9:56:59 P.M., Grant writes:
Mark, I'm going over my new (1981 Century Resorter) boat, and have a question.
I don't have a service manual for my boat, and the one I do have (for a '73 model) makes no mention of this situation. (See photo and text later.)

It seems to me it is a safety issue -- if the diaphragm in the fuel pump develops a leak, gasoline is captured in the glass sight bowl, warning of pump failure, needing pump replacement.
(The label says "REPLACE FUEL PUMP IF GAS APPEARS IN THIS BOWL." See photo later.)
On a friend's '73 Resorter, the glass bowl is dry, but on my '81 boat, there is what appears to be oil in the bowl. (Later found it to be old gas and other crud.)
Can you think of any reason for the oil?
(I have seen the same setup on another boat -- without the oil -- and thought the sight glass was from an old, abandoned fuel filtering system, but now realize it is a safety feature; to warn of a leaking diaphragm.)
Here's the glass in the 1973 boat:

On Sep 30, 2011, at 10:04 PM, Mark wrote:
Did you clean it out & recheck, did it reappear? or is it old? My guess is it's either old nasty gas, or engine oil that is migrating through the pump ... on old mechanical pumps, sometimes when they fail they would leak oil, or gas ... is the pump rebuildable?
I would clean & recheck first.

Grant replied: OK, Thanks.
I'll clean it out, then when I run it to warm the oil for its winterization oil change, will check it again.
(I have to figure out how to feed cooling water to the boat in my driveway, anyway. i.e., via pickup pictured below.)
I saw one of the (similar?) pumps, with glass bowl, for about $150 on ebay. I don't know if they are rebuildable, but the dealer I bought the boat from might know.
I'll ask them later. I also have a number for a guy in St. Charles, MO who works on only these types of marine engines. I can ask him, too. (And, another guy in northern Illinois Ted Carter, 847-395-8902.)
Thanks very much. I'll let you know what I find.

10/1/11: The stuff in the sight glass was cruddy gasoline. No doubt about it. I did not remove the pump, but it looks like it is rebuildable. Tough to get a good photo of it, though. Notice -- the "AC" brand. I'll remove pump later this week. Also note its name, "dual diaphragm."


On Oct 2, 2011, at 7:13 AM, Mark wrote:

I'm sure you can rebuild that one if you can get a kit, although if you can find a new one at the auto parts store, they are usually pretty reasonable. The leak looks minor, but if its old, you may want to do it as a precaution. There are 2 rubber flat diaphragms like a sandwich (one on top, one on the bottom) with a plate between them ... It's usually a very easy procedure.

You can take the pump to my friends at S&S auto parts (you went there for bearings) and ask to see Bill ... he will probably know what you need. (I did, no luck.) The only thing that looks different to me (from standard automotive design) is the glass bowl thing, my guess is its a marine requirement to catch any fuel leaks and limit the risk of fire.

Can you tell me what engine it has in it & about what year it was made?

10/2/11 -- Mark,
It's an '81 Chevy, I think. (That's what I was told, but have not confirmed. I'll look for a number.)
I'll get the pump removed Tuesday or Wednesday.
Located the manual on a similar boat (1973 Resorter with Ford V-8) that says the pump can't be rebuilt. Here's a .pdf:


Here are some photos of the fuel pump removerd:
The pump was difficult to remove, because of its location. I first removed the fuel line supplying the filter and tied it out of the way, then easily removed the fuel filter. (New one on order.) Before I re-install it, I'll remove the front seat to gain better access to the two compression fittings. (This has been done.)

On 10/6/11, I ordered a new AC 18-7274 fuel pump from Marine Parts Source via ebay.

Received new pump and will install it when I can gain clear access to its location on the engine. That may be a while. (See Front Seat.)

11/11/11 -- Now have the front seat (and the back seat) out of the boat. Greatly improves access to the fue pump/water pump area. Mark will install the new pump tomorrow, 11/12/11.

11/12/11 -- Took the boat to Mark's (home) and he installed the new pump. (I was nervous about getting the push rod placed properly.) After pump was installed, we ran the engine. BUT -- the pump's female threads for the sight glass was plugged with a plug that could NOT be removed. Mark tried using a long lever arm on the (metric) allen wrench, then tried an air-powered impact wrench. Nothing would free that plug. So, we concluded the manufacturer did not want it removed, and if a diaphragm leaked, it would leak into the engine block, and not the bilge.

That's Mark. Engine running.
Notice water from exhaust.


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