Engine Tick or Knock?
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=18069
Printed Date: April-28-2024 at 11:06pm
Topic: Engine Tick or Knock?
Posted By: flipflop
Subject: Engine Tick or Knock?
Date Posted: June-15-2010 at 6:21pm
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First post. Novice mechanic and beginning to learn about nautiques. Hope to be a Nautique owner in the near future, so bare with me
My friend has a 1990 sport nautique, PCM 351 with 1250 hours. Just had the transmission replaced and first time on the water the boat developed a loud tick/knock at idle and while running. It can only be heard under load and while underway. The sound is more pronounced the longer the engine runs. My first thought was a stuck lifter as the boat sat around for six months during repair. I searched the forum and came up with an action plan: A. Use screw driver and stethescope to pinpoint origin. 1. Change oil. 2. Try Rislone. 3. Check spark plugs/distributor cap - one at a time. 4. If noise doesn't improve move on to second phase. I know it may be something else, just trying the low hanging fruit first. Let me know what you think. |
Replies:
Posted By: eric lavine
Date Posted: June-16-2010 at 12:47am
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pull the plug wires one at a time while running and try to isolate noise,
did you replace the damper plate along with the transmission? Valve train noise is half speed of crank noise, it may help while listening to determine. a stuck lifter is pretty noisey and at times will sound like a rod knock but at half speed because the cam will spin once and the crank twice on each complete stroke. but first things first, pull the wires one at a time while running ------------- "the things you own will start to own you" |
Posted By: davidg
Date Posted: June-16-2010 at 1:03am
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Something else it could be is what plagued me for the past two years....bad exhaust gaskets! When they burn through the fiber that is stamped on the metal, it will make a popping sound, and lead you to believe it is something more serious. You may want to take off the exhuast manifold(s) and check them out. Yes, its a PIA, but, may be a lot easier and lower cost than taking the engine apart.
The solution: Percy's XX Carbon Gaskets made for such a situation, along with some high temp Copper gasket material to fill in any low spots on the head exhaust port where the exhaust gas may be burning through the gaskets. Or: Pull the heads and have them, or the ehxaust manifolds, machined flat to eliminate low spots where the gas burns through. I opted for the solution above as I didn't want to pull the heads right now. Let us know what you find the issue to be. |
Posted By: flipflop
Date Posted: June-23-2010 at 12:05pm
| Changed the oil for the first time. Everything went well. The noise starting becoming more audiable at idle. We narrowed the position down with a screwdriver. It is coming from the front center of the engine about 4-5 inches from the throttle body and more towards the left side before the camshaft cover. We were thinking it may be the raw water pump. Any ideas, I am going research the manual a little more and see what comes up. Thanks. |
Posted By: GottaSki
Date Posted: June-23-2010 at 12:25pm
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Then take the belt off for a moment and see what happens. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: flipflop
Date Posted: June-30-2010 at 1:32pm
So we narrowed the source to the area in the red circle above. Any thoughts to problem areas here. The boat has 1250 hours on it and the engine has been rebuilt. The noise is an internal tick/slight knock. Any chance it could be the timing chain? What are your thoughts? |
Posted By: 79nautique
Date Posted: June-30-2010 at 2:10pm
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lifter or rocker arm ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Jake
Date Posted: July-04-2010 at 4:25pm
A buddy has a '93 Sport. We had the same tick tick tick in the engine when it was at idle. Above idle, the ticking seamed to go away a little. Then last year we lost the motor. The picture is of the number 6 piston. Sorry about the size, I wanted to show the detail. There is a chunk missing near the bottom edge. Hopefully you don't have the same issue. I've also had bad timing make a pretty good tick tick tick (more of a miss and a tick). I'd check plugs, wires, points (if you have them), distributer cap for this type of noise. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1931&sort=&pagenum=2&yrstart=1979&yrend=1979 - My 79 Nautique |
Posted By: flipflop
Date Posted: July-12-2010 at 4:01pm
| Thanks for the response. We're keeping an eye on it. It's not my boat so it's tough to find the time to work on it. I have to lug my tools around with me. |
Posted By: behindpropeller
Date Posted: July-12-2010 at 4:07pm
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eric lavine wrote:Posted By: flipflop
Date Posted: July-13-2010 at 12:23pm
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Not sure what a damper plate is. Googled this:
http://www.alberg37.org/Project%20DB/SHEARWATER_DamperPlate-08/Transmission_Damper_Plate_Install.htm and http://skidimforum.com/ski-nautique-transmission_topic149.html We changed the oil and only about 2 qts came out. After oil change the boat has been running better. Our hope is one of the lifters/valves dried up while it sat. Especially over the winter. Thanks for all the advice. I enjoy learning about the older nautiques. Currently looking at an 89 2001 for myself. I like the smaller models. The 21' - 22' boats are a little big for my yard. |