Testing Alpha one Gen 2 water pump with no gear oil

[1focus]

1987 Mercruiser 3.0LX, Alpha One Gen 2 drive. When put to bed last fall, temp was fine, 145 on muffs winterizing. This year, overheats on while summerizing. Split outdrive, changed impeller, old one (last year) looked decent, a little soft, but no breakage. Reinstalled lower, overheats. Change thermostat, still overheats. Pull hose to exhaust manifold, flush...good water flow out. Drain and split drive...possibly didn't get water tube mated to pump. Disassembled housing, checked impeller, checked walls of housing. All good. Reinstalled pump housing and guide, reinstalled lower. Still overheating. Disconnect fresh water hose from Tstat housing, blow on it...clear. Start engine back up...no freshwater coming in. Draining drive oil again as we speak. Two questions: #1, after splitting drive again and checking water tube alignment, is it OK to start engine without lube in drive for just a minute to see if I have fresh water coming in? #2 Is it OK to use a small section of PVC as a "guide tube sleeve" to ensure the pump and water tube are aligned to mate up? I do have the coupling assembly, but I think my old outdrive had a "sleeve" to aid alignment. Thanks in advance for the help.

 

[dubs283]

1987 Mercruiser 3.0LX, Alpha One Gen 2 drive.

gen ii was introduced in 1991, perhaps yours is not original to the boat/engine package?

oem water pump kits for both alpha one and gen ii come with a white guide tube to aid in lining up the water passage tube to the housing

a lot going on in your post, to my understanding you have removed the hose at the t-stat housing from the transom, i.e. the output hose from the drive water pump an no water is present with the engine running? if so, one of three things, hose/passage is either blocked or disconnected somewhere, impeller key is missing, or driveshaft in gearcase assy is not turning

i would not run a drive without gear oil ever, even if momentarily for testing purposes.

 

[Bt Doctur]

are you using ear muffs? The gen II uses a coupling on the pump base and a 3 inch guide tube inserted into that

 

[1focus]

are you using ear muffs? The gen II uses a coupling on the pump base and a 3 inch guide tube inserted into that

yes, using muffs. I have the coupler with two seals and the water tube, but no guide tube. My old Mercruiser outdrive, I'm positive had a guide tube, this is an SEI, and it doesn't. I just got back from Menards with some clear tubing that fits over the outside of the coupling assembly. Going to give it another go. Thank you for your help!

gen ii was introduced in 1991, perhaps yours is not original to the boat/engine package?

oem water pump kits for both alpha one and gen ii come with a white guide tube to aid in lining up the water passage tube to the housing

a lot going on in your post, to my understanding you have removed the hose at the t-stat housing from the transom, i.e. the output hose from the drive water pump an no water is present with the engine running? if so, one of three things, hose/passage is either blocked or disconnected somewhere, impeller key is missing, or driveshaft in gearcase assy is not turning

i would not run a drive without gear oil ever, even if momentarily for testing purposes.

Thank you for the kind response. I apologize, in my haste, this is a 1997 3.0LX with a replacement SEI outdrive I installed in 2016. Hose passage is clear as I can run run water backwards and it exits through the drive, key is inplace. Turning driveshaft will turn prop shaft. I really think it is due to water tube not getting mated to coupling assembly. As I have filled and drained leg three times, wanted to see if it was acceptable to fire motor momentarily with fresh water feed tube disconnected from Tstat housing, just to see it would get water after installing guide tube. I guess I'm getting good at draining it, so here we go again! Thanks for your advice, I will follow it!

 

[1focus]

I found out it wasn't the fresh water pump...apparently the water hose on the outside of the transom has an issue. Possibly mice from over winter indoor storage. Looks like a bigger job next weekend. Ordered bellows along with hose in case they are in bad shape when I get in there. Oh well, at least I don't have to drain the gear lube again!