Slight surge at top end
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=42977
Printed Date: October-06-2024 at 4:27pm
Topic: Slight surge at top end
Posted By: Stevo89
Subject: Slight surge at top end
Date Posted: June-17-2018 at 4:59pm
| Back story: I bought a 1990 Ski Nautique 351w about two years ago which had sat for two years prior me purchasing. After buying it we replaced the plugs and had a compression test done ( which came back fine) and timing set. the boat ran good for a few trips out then started to pop in the carb and hesitate on take off. Sent the carb out to be rebuilt put it back on and still had hesitation and couldn’t pull a skier with out stalling. So frustrated I ordered a new quick fuel carb to replace the holly . After the carb swap boat ran good for about 2.5 hours then cut out and wouldn’t restart. Dropped it off at the marina with a box of new electrical tune up items I ordered ( rotor, distributor cap, plug wires,coil, fuel water separator) found out the gear on the distributor sheared off. Got a new distributor installed ( he also put all the other parts I had on. Took the boat out to test run it and I noticed at 3/4-7/8 throttle it runs great anything above that I get no extra rpm, power, or speed but the boat will slightly surge like it wants to keep going. Any ideas I thought fuel/air mixture screws or fuel pump air leak/ fuel or air restriction any suggestions of where to start? Thank you in advanced and happy fathers day to any dads out there |
Replies:
Posted By: KENO
Date Posted: June-17-2018 at 6:19pm
|
You should probably post more info. There's a post on PN by somebody with the same screen name with the same problem with a lot more info provided  Putting the same info here would sure be helpful. I'd figure out too if that distributor that starts with a P is a newer Pertronix or a Prestolite like the original was. |
Posted By: SNobsessed
Date Posted: June-17-2018 at 7:40pm
|
What is the total timing at WOT RPM? I am not sure how a QF carb works, but you could have someone observe secondary throttle plate link to see if it varies with the surge. Obviously leave doghouse at home . . . ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: KENO
Date Posted: June-17-2018 at 7:42pm
|
Since your latest issues happened after shearing the distributor gear and replacing it with another one I'd be looking at the ignition system since your fuel system seemed OK before the gear issue.. You said on PN it's a Prestolite with a screw down cap. Was this a New Old Stock distributor that was installed? Or maybe a used one? What's your timing both at idle and since you can only get to 3000 rpm's what is the timing at that speed? |
Posted By: Stevo89
Date Posted: June-17-2018 at 8:12pm
| I will check the ignition brand when I get off work today and re write a more detailed post |
Posted By: KENO
Date Posted: June-17-2018 at 8:16pm
|
Just do a cut and paste from over "there"
|
Posted By: Stevo89
Date Posted: June-17-2018 at 8:18pm
Sorry in advance I have very little experience with mechanical work altho I do under stand the basics and can do some trouble shooting. This is also the first inboard boat I have ever been in let alone owned. And it have never quite ran right  story of my life
|