RWP priming question - '87 SN 2001
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Category: General Correct Craft Discussion
Forum Name: Common Questions
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URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=35753
Printed Date: September-26-2024 at 12:54am
Topic: RWP priming question - '87 SN 2001
Posted By: xarmypilot
Subject: RWP priming question - '87 SN 2001
Date Posted: April-12-2015 at 12:30am
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On our old Chris~Craft, before first start and after changing impellers we used to have to prime the RWP by removing the cover and pouring water down the intake side of the housing. Is the process the same for my '87 SN? Is there an easier process without removing the RWP cover? Should I even be concerned? ------------- '87 SN 2001 http://mbbw.com/WIP/DSCN9620.JPG" rel="nofollow - '68 Chris~Craft Grand Prix (Past family boat) '72 Checkmate Mx16 (Past family boat) "Speed is life, altitude is life insurance" |
Replies:
Posted By: 75 Tique
Date Posted: April-12-2015 at 12:35am
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Doesn't need priming. Fire it up. Just make sure its pumping water and not just running on water pressure from a hose. So either in the lake or with the water intake hose drawing out of a bucket is the best assurance that its pumping. ------------- _____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
Posted By: xarmypilot
Date Posted: April-12-2015 at 12:59am
That's a very good point regarding the water from the hose  . I haven't had a chance to run over to ACE to build a "Timmy Tee" so I'll probably be using the toilet plunger method for cooling. Do you think the positive water pressure will still be a factor? ------------- '87 SN 2001 http://mbbw.com/WIP/DSCN9620.JPG" rel="nofollow - '68 Chris~Craft Grand Prix (Past family boat) '72 Checkmate Mx16 (Past family boat) "Speed is life, altitude is life insurance" |
75 Tique wrote:Posted By: Hollywood
Date Posted: April-12-2015 at 5:00am
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A factor in what? ------------- |
Posted By: 74Wind
Date Posted: April-12-2015 at 5:28am
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Ok I'm confused. Have never heard of this priming thing. My 1974 has been sitting since October. Per usual, just charged battery and it fired up fine first turn of the key/season today and ran great all day. Are you having some problems? I say skip the hokey fake a lake plunger, put it in the lake, fire it up and see what happens you may be pleasantly surprised and realize you may be over thinking it... .. ------------- 1974 Southwind 18 1975 Century Mark II |
Posted By: 8122pbrainard
Date Posted: April-12-2015 at 8:14am
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Rob, Unless your Chris was pre WWII, you should of had a rubber impeller RWP which shouldn't need priming. Something was wrong. If pre WWII, then gear pumps were still used on some engines but they would have grease cups that would be screwed in to pack the gears to prime with grease. The Timmy T or the Fake-A-lake plunger methods both can hide RWP problems with pressure from the hose. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: April-12-2015 at 11:23am
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I use dish soap when reinstalling an impeller. Gives it some lube until the water gets there. But it shopuld be OK even without that. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: xarmypilot
Date Posted: April-12-2015 at 12:53pm
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Sincerely appreciate everyone's input. I guess my general take-away is that most likely I won't need to prime, but the possibility of the flush technique being used could end up masking some RWP problems due to positive water pressure being created by the hose. Taking all factors into consideration, I see that Larry and Pete both allude to the fact that the preferable method would be just using a bucket full of water on the input side. This makes perfect sense to me. It ensures that the RWP is producing enough draw for ample cooling and isn't suffering from any air leaks or other issues that may masked due to the positive water pressure. Kinda killing two stones with one bird... Many thanks! ------------- '87 SN 2001 http://mbbw.com/WIP/DSCN9620.JPG" rel="nofollow - '68 Chris~Craft Grand Prix (Past family boat) '72 Checkmate Mx16 (Past family boat) "Speed is life, altitude is life insurance" |
Posted By: CrazyCanuck
Date Posted: April-12-2015 at 2:02pm
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i don't think that water pressure is a factor. The impeller won't take any more water from pressure, plus the fake a lake is not a perfect seal. I have not had any problems with my toilet plunger so far.....lol. ------------- https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcRtW3vJrMHLdqBzndt9VX3oOpBuRopGlzKq9Ea7pAO7wnTuoD8E8g |
Posted By: 75 Tique
Date Posted: April-12-2015 at 4:03pm
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I think you missed the point corey. Its not about the impellor taking more pressure, although I'm not sure what that means. The point is, if you run on a hose, the hose can push the water though the engine. It can mask a situation where the pump is turning but not pulling any water, so you think its fine in the driveway and you get to the lake and you over heat. Pumps can turn, but if there is the least little bit of an air leak between the pump and the lake, you will not get any, or at least enough water. Many here, including me, have seen this. Running on a hose (or plunger) is fine for a quick engine test or warm up in the driveway, but it is not the way to go to verify that your pump is good. Pete, I could be wrong but I think a Timmy-T is fine for testing a RWP. I think the easiest path for the water to follow is out the thru-hull and that is would take "full suction" to divert the flow to the engine. But I could be wrong, maybe pulling from a Timmy-T takes less than perfect suction. That, I don't know. Bucket's the best, I guess. ------------- _____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
Posted By: xarmypilot
Date Posted: April-12-2015 at 4:50pm
Agreed, but I would say that all would be dependent upon the reason for the run up. If you have no cooling issues and just want to start - say to heat up the oil in preparation for a fluids change - then no worries. If you are attempting to preform a engine & cooling system diagnostic, then you'd likely want to go with the bucket. ------------- '87 SN 2001 http://mbbw.com/WIP/DSCN9620.JPG" rel="nofollow - '68 Chris~Craft Grand Prix (Past family boat) '72 Checkmate Mx16 (Past family boat) "Speed is life, altitude is life insurance" |
Posted By: 75 Tique
Date Posted: April-12-2015 at 4:53pm
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We're on the same page. That's why I said its fine for a quick engine test or warm up. ------------- _____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
Posted By: 8122pbrainard
Date Posted: April-12-2015 at 5:11pm
Corey, Yes, you missed the point about the pressure. Larry, I feel you are half way correct with the Timmy T not producing pressure to mask air leaks. Even though it dumps excess water out the intake, it does produce some pressure. The placement of the T is also a concern. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: CrazyCanuck
Date Posted: April-12-2015 at 7:12pm
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I don't think I missed the point. I just worded my point poorly. What I was trying to say, is that with a fake a lake, there is no direct hose connection from the house to the boat. Therefore house pressure could not transfer through the motor. Perhaps with a T line it could, but I don't think that the way a impeller is designed that much house pressure would bleed through anyway to mask a poor impeller. Unless of course the impeller was shot and did not form a tight seal inside the housing. I could be wrong on that.....but that is what I was trying to say. ------------- https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcRtW3vJrMHLdqBzndt9VX3oOpBuRopGlzKq9Ea7pAO7wnTuoD8E8g |
Posted By: 8122pbrainard
Date Posted: April-12-2015 at 7:29pm
Your wording is still off!  It doesn't matter what type of device you use to artificially get water into the system. The RWP creates suction under normal conditions and will suck air from any bad point on the suction side. The hose bypasses the problem. It also bypasses a bad impeller that doesn't create any suction. Don't worry about pressure transferring to the engine. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |