78 ski nautquie.. propeller and prm issue
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=43024
Printed Date: April-28-2024 at 7:50pm
Topic: 78 ski nautquie.. propeller and prm issue
Posted By: Eric Harrell
Subject: 78 ski nautquie.. propeller and prm issue
Date Posted: June-24-2018 at 1:46pm
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Hey Guys.. hope all is well... I have a 78 SN..351w... I put on a new QFT.. but I can only get 2900 rpms.. under pressure.... so secondireies will not open... at idle I get all I want.. my current propeller is 13x14. FRDERAL RH.......... HELP.. PLEASE ------------- Easyyelp |
Replies:
Posted By: MACS81SN
Date Posted: June-24-2018 at 2:09pm
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Check your throttle cable movement at carb. Not familiar with QFT but you may have to make some adjustments from how the 4160 linkage was set up to get primaries to fully open. Recent poster had similar issue. ------------- Mark 1999 -SN - 502 Python 1981 - SN Owned 33 years - Sold 1968 - Mustang - Sold |
Posted By: Eric Harrell
Date Posted: June-24-2018 at 2:33pm
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I disconnected the cable.. the throttle is in same location if I use my hand or have it connected ------------- Easyyelp |
Posted By: MACS81SN
Date Posted: June-24-2018 at 3:31pm
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To make sure I understand what you said. You can fully open primaries by hand with cable disconnected and the throttle cable will also fully open the primaries? What do you mean by “under pressure?” Did you do anything else to the engine while changing out carb, any details you can provide can help isolate the issue(s), ------------- Mark 1999 -SN - 502 Python 1981 - SN Owned 33 years - Sold 1968 - Mustang - Sold |
Posted By: Eric Harrell
Date Posted: June-24-2018 at 4:33pm
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Under pressure.. in gear and moving.. in neutral I can hit 3000+ rpms.. only 2800 when running.. even coming out of hole.. yes.. I watched the secondireies open.. in neutral at 3100rpms.. ------------- Easyyelp |
Posted By: KENO
Date Posted: June-24-2018 at 5:00pm
That should never happen in neutral with no load unless you have mechanical secondaries and you bought a M-600 QFT right. It has vacuum secondaries. |
Eric Harrell wrote:Posted By: 63 Skier
Date Posted: June-24-2018 at 5:41pm
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Have you checked timing, especially total timing? If your distributor isn't advancing correctly it will limit power. ------------- '63 American Skier - '98 Sport Nautique |
Posted By: gt40KS
Date Posted: June-24-2018 at 5:42pm
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3000 in neutral and 2800 in gear is no surprise ... with a load on the drive train the engine will always max at a lower rpm. What more concerns me is the 3000 max in neutral - got to be a problem there. Fuel restriction? Carb malfunction or linkage problem? IDK, I'm no carburetor guru.... there's others on the site much more qualified for that question. But if you are saying no load in neutral is 3100 or so max rpm, there is an issue. ------------- JCCI 1995 Ski Nautique GT40 |
Posted By: MACS81SN
Date Posted: June-24-2018 at 6:00pm
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Ditto what Ken said. It’s difficult to isolate whether this is a fuel or ignition problem as I’ve seen both cause similar symptoms. That’s what I asked if anything else had been done like new spark plug wires or etc Assuming only the he carb was changed, I understand some point nstallations require a USCG approved rubber fuel line to change necessary for he carb to the fuel pump or existing fuel line. I’ve seen where small pieces of rubber have been inadvertently sliced off the rubber is hen pushed on to barbed adapters fittings. The piece(s) have then blocked the inlet, needle valve, and one or more jets. I would check your fuel pump pressure which should be 5-7psi. It takes little fuel to rev an engine in neutral vs under load. ------------- Mark 1999 -SN - 502 Python 1981 - SN Owned 33 years - Sold 1968 - Mustang - Sold |
Posted By: MrMcD
Date Posted: June-25-2018 at 5:00am
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Something is way off, I owned a 1978 Ski Nautique with the 351W and I used a 13x14 through 8 years of ownership. Mine would turn it above 5,000 RPM at 500 ft elevation. Much less at 6,500 Foot Lake Tahoe elevation, 4,400 RPM, if I remember correctly. On that boat I had issues with the carb at times. When I wanted to test and see if the 4 bbl was opening I just opened the engine cover, had someone else drive and watched the carb. You can see and hear the secondaries open or not. ------------- |
Posted By: Eric Harrell
Date Posted: June-25-2018 at 10:16am
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Thanks all.. so the qft 600 is new.. it will reach more rooms. In neutral I just stopped revving the engine once I saw them open.. the distributor is old it is electronic.. not points.. when I say old.. it's 20+ years or older.. so new and new timing?? ------------- Easyyelp |
Posted By: 8122pbrainard
Date Posted: June-25-2018 at 10:28am
Why? Are the bushings bad? Have you checked the timing?
BTW, I've got some old distributors that still work fine and they have point sets! Let's see, one is 64 years old and another is 54 years old. The 77 is 41 years old but it's got and EI  ------------- /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: MrMcD
Date Posted: June-26-2018 at 5:29am
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Put a timing light on it and while watching your timing marks slowly raise the RPM from idle to 3,500 RPM. The timing should advance from around 10 at idle to 32-35 at 3500 RPM. It should advance smoothly each and every time the exact same. If it does not advance properly your engine will run like a dog. No power on the top end. ------------- |
Posted By: samudj01
Date Posted: June-26-2018 at 11:55am
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Sounds like the problem we were having with our Tique last summer. It ended up being a timing issue PLUS an issue with our distributor springs not allowing a smooth nor consistent advance. These guys got us rolling and increased our knowledge! Start with timing and go from there. ------------- 78 Ski Tique, 72 Skier w/302's, 93 SN w/351 & 17 GS22 w/zr409 Previous - 99 Sport Nautique w/GT40 and 87 Martinique w/351 |
Posted By: Eric Harrell
Date Posted: July-02-2018 at 2:13pm
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Ok... back from Vacation and now on to boat repairs.. I am going to buy a new cap at rotor.. I have a Marine distributor.. list# 428 D.. what cap and rotor do I buy and where?? Thanks E ------------- Easyyelp |
Posted By: KENO
Date Posted: July-02-2018 at 2:31pm
That number doesn't mean much but if you follow the link below you might find a picture of your distributor, then you'd know what to order from the same place  https://www.skidim.com/distributor.asp" rel="nofollow - link The quote below from an ignition outfit explains the 428D you reference and also the SAE J1171 you'll probably find too. "Please note that SAE J1171 and UL 428D are NOT distributor part numbers, but simply US government standards that many completely different distributors meet. These numbers are of almost no use in determining which distributor you have or what ignition kit you need. Usually, the Prestolite distributor part number will be on the opposite side of the distributor body." |