5.0 still missing... Please Help Info inside UPDATED

[Friscoboater]

Well I took the boat out this weekend and had the same problem. Runs great for about 30 minutes and then there is not power and will sputter and spit when you hit it. I bought this boat about a month ago and the guy had just had the points, condenser, plugs and wires replaced. Well being a car guy and built alot of engines i should have checked that when I was doing my other change outs. it seems that the mechanic that did the work custom made the plug wires. Well the most important wire that goes from the coil to the distributor was made incorrectly. He did not fold the center conductor over when he crimped the end on. The end is all black and charred. How it ran in the first place I have no clue. I had a mustang that did the same thing a long time ago, and I should have remembered that.

So if anyone has a motor that runs like you have water in the gas, check your plug wires.

I hope this helps someone.

I will test it this weekend and let you know for sure.

*************
UPDATE:
*************

I took it out today and things were better, but still after about 15 to 20 minutes the boat will stutter and spit out of the hole and then surge at high rpm. Kinda feels like one cylinder is not firing all the time. It will catch and run great for a second but then just sound and feel out of it.

The weirdest thing is that when I hit the trim button the boat looses power. Some I am thinking electrical, but I just do not know where to start.

Could the carb be causing this? I am not sure it has ever been rebuilt, and I would jump in and do it right away, but this to me just does not seem like a carb issue.

Here is a list of what has been done

Boat: 81 Glastron SX-190
Engine: 305 with pre alpha stern drive

Replaced:
Cap
Rotor
Points
Plugs wires
Condenser
Fuel Pump
Both Filters
Fuel is fresh

I am open to suggestions. I think I will by a rebuilt kit for the carb tomorrow. Can I just get on at autozone?

 

[gadget73]

Re: Eureka!!!! 5.0 missing solved... I think

Re: Eureka!!!! 5.0 missing solved... I think

Cool. Honestly I'm impressed someone even bothered to custom make plug wires. Haven't seen anyone do that in a long time, unless it was for their personal vehicle.

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

Updated at the top with questions.

 

[JustJason]

Re: 5.0 still missing... Please Help Info inside UPDATED

check your voltage at the coil positive with the engine running. (NOT NOT NOT the high tension lead!!!!!!) Hit the trim switch and see if the voltage drops.
Do it when the problem appears... not before or afterwards.

 

[Hansolo99]

Re: 5.0 still missing... Please Help Info inside UPDATED

It might be a valve sticking??

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

I never thought of a valve.

 

[PBJMAN]

Re: 5.0 still missing... Please Help Info inside UPDATED

My first post! It's long, but it may have an answer to your problem. If you haven't done it already, then check your battery/alternator/belt.

I was having similar problems, 1987 Bayliner Capri with OMC 3.0. I bought it a month ago and it would run good at startup but after a while of cruising, would start to run rough, missing/backfiring, so I would then have to limp back in to the ramp. After several outings, I eventually did fuel additive, new carb filter, new fuel pump filter, added a fuel/water seperator, tried spray in carb cleaner, plugs, condenser, points, cap, rotor, etc. During the trial/error process of taking it out, then fixing something, then taking it out again, I wore the battery down from frequent starting & stalling, so I got in the habit of putting it on the charger every couple of days. (Missed a clue there, didn't I?!)

It started easier and ran smoother, no stalling at low rpm's, but every time, after a while of cruising it would do the same thing. It seemed like a heat-related issue, but I wasn't overheating. So frustrating! I read a lot of forum posts and asked the local shop guys.

Finally, I had a guy come to the house to hear it run on the muffs. He looked the engine over a bit and asked me "How long has that belt been loose?" (alternator belt) I said, "been that way for a month, it can't adjust out any longer and I just haven't got around to changing it yet cuz and I've been trying to get it running good first." He then ran the engine, checked my plugs, point gap, timing, looked down the carb, etc and said it was all good and the motor sounded real good. As he was leaving, he suggested I change the belt and also check the ignition coil after the next run to see if it is getting hot.

My hopes were in the loose belt. If the battery is not charging enough, might mean the loose belt is the problem or possibly the alternator itself! I got out the volt-meter and put it on the battery with the engine off: 12.06 volts. I started the engine, idled it up to about 1200 rpms: 12.06 volts. I realized that the alternator was dead, causing everything to run off of the battery. The coil needs a lot of juice to make spark for cruising speeds, without the alternator working it was sapping the battery forcing me to limp in. A new alternator (and a proper sized belt) has solved this problem for me! Now it runs like a car, starts easy, doesn't stall, idles well, no backfire, no gas smell, etc. I'm happy!

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

I had a loose belt too , so I replaced it and the Alt is new. The volts shoot to 14 or so when running so i know it is getting good juice. I really thank you for your post, and your advise.

 

[snoski]

Re: 5.0 still missing... Please Help Info inside UPDATED

As we say in the MGB world when the car starts running rough and giving us problems, "it's usually not the carbs".....

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

I will try some of these suggestions. The thing that is really puzzling is the trim button making the motor loose power.

 

[PBJMAN]

Re: 5.0 still missing... Please Help Info inside UPDATED

I will try some of these suggestions. The thing that is really puzzling is the trim button making the motor loose power.

That could be a symptom of a bad coil. Does your blower or bilge do it too or just the trim? The mech. who looked at my boat suggested I might suspect the coil if it feels really hot after running at cruising speed, although in my case that turned out to not be the problem.

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

Could a coil be doing that after it gets hot?

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

I replaced the coil last night and it was in pretty bad shape. it looks original (30 years old) and the ground wire from the coil to the distributor was frail and broke off in my hands. It was oxidized badly so I replaced it also. Once finished the engine seemed to spring to life much quicker, but the proof will be on the water.

Wish me luck.

 

[dubs283]

Re: 5.0 still missing... Please Help Info inside UPDATED

if you have one bad/oxidized elecritcal connection its a sure bet you have many. go through the entire motor electrical and clean/replace any and all bad connections

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

I went over alot of them and they seemed ok. The Dist is right under the seem on the sun deck (I know bad design) so every time a skier gets in the water goes right down on top of it. All the other electrical connections are out of the way.

 

[maxxman04]

Re: 5.0 still missing... Please Help Info inside UPDATED

yes, a coil will act like that, shutting down when it gets too warm. most definately tho, check every single connection everywhere, make sure they are good. it only takes that one wire you can't see or didn't check to mess ya up.

 

[rbh]

Re: 5.0 still missing... Please Help Info inside UPDATED

like every one else said "check your connections" start at the battery, pull off all the cables, clean to bare connector or replace and do the battery posts, tighten down battery nuts good and tight, nothing should be loose a little dielectric grease on top of cable connectors will help. next fire up the engine and do a dc volt test, should be 13.5-14.5 vdc while charging off engine.
you will find a voltage drop will really affect performance.
rob

 

[Friscoboater]

Re: 5.0 still missing... Please Help Info inside UPDATED

It seems like it is all fixed. I took it out on the water this morning and it ran the nest it ever has. I was able to hit 50mph on the GPS and I have never been to get above 40. The power was awesome and it was so nice.

Thanks for all your help guys.