Engine misfiring and cannot figure it out
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=39596
Printed Date: October-07-2024 at 6:29am
Topic: Engine misfiring and cannot figure it out
Posted By: AKskier
Subject: Engine misfiring and cannot figure it out
Date Posted: August-05-2016 at 10:04pm
Folks:
Looking for some mechanical insight:
Boat: 1994 Ski Nautique
Engine: 5.8 Pro Boss, Pro tech efi
Hours: 240 original
Condition: Mint show room condition, I am the third owner
Issue: Intermittently the engine seems to miss fire at either 200o rpm or at 3000 rpm. The boat makes a shaking sensation, like the shaft is out of alignment, though the shaft, prop, and cutlass bearing are fine. It is almost like half of the cylinders are firing or perhaps only half of the cylinders are getting gas while the other four are being shorted of fuel.
Any ideas of comments? I am in rural Alaska and a ways away from a mechanic. Would greatly appreciate some mechanical advice and insight.
AKskier
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Replies:
Posted By: 8122pbrainard
Date Posted: August-05-2016 at 10:14pm
Eric,
Welcome to CCfan. I may be mistaken but I don't recall another member from Alaska so it's great to add another state to the list.
What you are describing sure sounds like another Pro tech on it's was out. Explore the site and you will find several threads on converting back to a distributor and a carb. The FAQ thread in the maintenance forum is a good place to start. It has links to the Pro Tech problems as well as almost anything else. If you can find what you are looking for, ask. I feel the members here are the best at any issue.
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/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
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Posted By: Jonny Quest
Date Posted: August-06-2016 at 1:24am
Eric:
I agree with Pete. It sounds like the ProTech engine management system is starting to fail. Some (myself included) feel that the ProTech is a ticking time-bomb that will eventually implode and fail. You appear to have the double-whammy with the throttle-body fuel injection ProTech combo.
Parts for the ProTech and the throttle-body fuel injection are no longer available. May be time for a retro-fit back to "old school".
JQ
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Current
2003 Ski Nautique 206 Limited
Previous
2001 Ski Nautique Open Bow
1994 Ski Nautique Open Bow
Aqua skiing, ergo sum
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Posted By: AKskier
Date Posted: August-06-2016 at 4:24pm
Thanks for your help, after 24 hours I have more info than I can imagine. I will go to FAQ and search Prp Tech and see what I can find.
JonnyQwest has also been amazingly helpful. 8 weeks to ski before the big chill and ice happens in Alaskaland
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Posted By: gun-driver
Date Posted: August-07-2016 at 12:57am
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You may also want to check your fuel pressure before replacing the whole package. I was on one of the other boat sites guy had same problem with that set up, ended up being the fuel pump or a dirty fuel pump screen can't remember exactly.
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Posted By: desertskier
Date Posted: August-08-2016 at 12:14pm
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Check the voltage at the 12.5amp breaker on the back of the engine, It should be close to battery voltage. The Protec system will act up if that voltage is low. Not exactly sure how low it can go but I think it is safe to say it needs to be greater than 10Vdc. The key needs to be on and if possible the engine running.
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