1990 Sport Nautique - Engine Failures/Issues

Hey all, hoping someone can help me out - apologies if I missed a thread that discussed my same issues. I found a few similar threads, both here and also on Planet Nautique, but never seemed to be the exact same, or the threads would die before finding a cure.

I have a 1990 Sport Nautique with the PCM 351 Engine with Edelbrock carb. I'll elaborate on my issues and maybe you can point me in the right direction. Boat ran fine before winterizing this past year, but due to some unforseen issues (my son broke his arm early spring), we weren't able to get on the lake as soon as we'd have liked. It sat from basically late December until about mid-July before I could get it out for a test run this season. I should also note I'm no mechanic and part of the reason for buying the Nautique was to learn and educate myself on some engine basics.

Here's what I'm dealing with:

First day out, it took a few cranks to get it fired up. It ran, with the throttle pin pulled out, for a couple minutes on the trailer, but as I went to put it into reverse to help slide it off the trailer a bit, the engine died on me. Fired back up and I was able to idle to the dock while I pulled my trailer off the ramp. Let it run while I moved the trailer and parked the truck, and then took her out for a couple laps. Idled out of the marina fine, drove it for about 20 minutes with no issues (checked under the hood for any leaks or issues and everything looked good), but as I idled back into the marina, the engine died on me about 20 yards from the dock - no sputtering or anything, just went from a perfectly normal idle to dead. Was able to start it back up and get it to the dock, but died again on me about the time I got tied up. Again, no sputtering or hesitation - just completely from idle to dead. tried to restart again to get it on the trailer and though the engine would turn over, it would not fire. I'd had my battery on the trickle charger during the offseason, so I had a good charge and the battery was replaced last season. Oil was changed along with oil filter, as well as new impeller last spring. Only put about 20 hours on her last season.

The next day, I tinkered a bit to check a few items - checked the fuel water separator to see if my gas had gone bad on me (filled the tank full and added Sta-Bil before winterizing) and the gas looked clean to me. That said, I was unable to get the fuel water separator opened up that day, and I plan to change out the filter, but haven't year. I also took off the distributor cap (running points as far as can tell) and though there was a bit of corrosion on some of the points, it didn't seem too bad to me. I did take a wire brush and cleaned the points off as best as I could. After cleaning the points, I removed the coil wire and grounded it on the block and tested for spark and seemed to have a decent spark from the coil. Reassembled everything and took it to the ramp again, hoping maybe it just needed a rest after her first run of the season.

On the ramp, she started up on the first attempt if I recall correctly, but then died on me on the trailer again. Started right back up though, so I idled over to the dock and tied up, moved the trailer and left it idling at the dock, and it was dead when I got back from moving the trailer. It fired back up again though and I was able to let her sit, idling at the dock, for about 15 minutes with no issues. I got brave and took it out to see if the kinks had worked their way out and it idled out of the marina just fine, got on plane just fine, went about 100-200 yards just fine, but then really started surging on me. Didn't matter what level of throttle I applied, it would not accelerate and continued surging on me as I aborted my test run and headed back to the marina. Surged for about the 100-200 yard trip back to the no wake zone, and died on me when I dropped throttle back to an idle. Was able to restart with the throttle pin out (out of gear) but as soon as I'd pop the pin back in and try to give forward throttle, it would die. Again, this time it would sputter some, clunk a bit, and fail. As I felt it fail, if I took it out of gear and revved the engine, it would recover, but anytime I attempted to put it into gear and idle forward, it would die/choke out. I was able to get towed back from a fella coming in for some gas luckily and then pulled it onto the trailer. I haven't been able to mess with it since.

My initial thoughts are that it's a gunked up carb potentially? I have some pics attached of a shot from above with the flame arrestor removed. The surging issue I believe is more carb related.

Also could be a bad fuel pump from a couple other threads with similar issues? I've not had a chance to diagnose the fuel pump or check the pressure. Maybe a fuel relay issue?

Finally...maybe my ignition coil is in need of replacement. The coil is pretty rusted looking and probably needs replaced anyways.

I've got spark...the gas didn't seem to be bad or have a lot of water in it (or any really after draining the fuel water separator for a sample).

I've owned the boat for about 4 years now and the only thing I've ever had fail on me was the alternator belt so I guess I'm lucky. I'm sure she could use a new coil...but I'm curious on thoughts about a fuel pump replacement, replacing relays, replacing dist. cap/rotor, etc.

The other issue I'm facing here though is tracking down part numbers. Can I use an ignition coil from advanced auto parts or do I need a marine specific? Can I spray some carb cleaner/seafoam into the carb to try to clear out any gunked up parts? Are these part fixes/swaps something a novice can handle, or should I take it to a mechanic. Again, I'm trying to learn some about caring for and fixing engines so part of me wants to try the fixes, but part of me also is dying to be on the water...

Your help is appreciated! Hope my description makes sense and my terminology is accurate and makes sense.

Since you asked about a coil from Advance Auto, a BWD E70 coil fits the bill.

1.5 ohms on my meter

If you're a Speed perks member and you dig up a 20% discount coupon, it'll be under 20 bucks

If you can't dig up an online coupon.............shame on you

KENO wrote: Since you asked about a coil from Advance Auto, a BWD E70 coil fits the bill. 1.5 ohms on my meter If you're a Speed perks member and you dig up a 20% discount coupon, it'll be under 20 bucks If you can't dig up an online coupon.............shame on you

Hi Ken,

Sorry to sidetrack, but after reading this thread I figured maybe you could help me out too.
I ordered a new set of spark plug wires for my 2000 Sport Nautique (GT-40 engine) but the set didn't come with a coil wire. Do you know where I could find just a coil wire, or which one would work?

Thank you

gun-driver wrote: Where did you get the wires? Should have come with a coil wire. https://www.skidim.com/prodinfo.asp?number=RK120015

So I'm kind of an idiot. I thought the OEM red spark plug wires looked kind of cool - and I noticed that the new wires have switched to the gray/black. I found a set of still packaged/never used OEM red wires on Ebay that some MarineMax was selling. Of course they get to me and I find out there's no coil wire in there.

Here's a link to Summit Racing and a search for "coil wire"

Most any auto parts store could probably get you just a coil wire too

I'd get a bright yellow one myself, that way I'd always know which one was the coil wire

link

I suppose if the wires were OEM PCM for a Pro Tec system you'd only get 8 wires since they had the coil packs and no coil wire was needed.

Quick question (with probably a long answer HAHA). How difficult is it to clean up an Edelbrock Carb? I'm thinking an issue for me may be that since my boat sat for about 7 months...maybe longer if you count the fall months it wasn't used before winterizing...the carb could be all gunked up from the gas that sat in the boat all winter. I plan to check the ASV, replace the fuel/water separator filter, and thought I'd clean the carb up as well in case any deposits have the jets clogged up - could be causing the surging I'm experiencing.   

I've watched a few YouTube vidoes on taking the carb apart...my question is, if I take it apart to be able to clean out the jets really well (and other areas while it's apart), how involved of a process is this? As mentioned before, I'm no mechanic, but the videos seem pretty straightforward on the disassembly/reassembly of the carb. Would I need a rebuild kit to be able to take it apart? I can't just re-use the existing gaskets I'm assuming. Does it make sense to rebuild it if I've already got it apart?

Thanks for the feedback!

I’ve watched countless videos on YouTube and it doesn’t seem too difficult. Attention to detail, yes, but it seems pretty straightforward.

Would an Edelbrock kit from advanced auto parts do the trick?

After reading countless threads I really am thinking by letting gas sit for 7+ months, it’s god the carb or fuel filter all gunned up.

Fingers crossed at least.

I thought it was stabilized...but I run premium 93 in mine since that’s what the previous owner had run and I didn’t want to change things up. If it was stabilized but sat for 7+ months...could that still cause me problems?

Brad,
I've never had a problem with stabilized fuel over my 6 or 7 month winter layups. This is even with ethanol that I've always run since day one when it came out. Unless an engine calls for high octanes, it's just a waste of money to use it. If the layup exceeds the 6 or 7 months, I add another dose of stabilizer.

You know what they say...................fugliness is in the eye of the beholder

I guess in your case, maybe you took it in the shorts on that coil wire

Here's somebody in the link who got 9 wires but has a funny colored coil wire

link

Seems like quite a few places show that gray coil wire with the 8 red ones for that part number

Update: the carb rebuild went very smooth and I believe was a key factor in what was going on with my boat. The float bowls were full of gunk/debris, the accelerator pump was full of gunk/debris, and the right side of my jets were clogged to where gas was only being delivered to the left side of the carb.

I also replaced the fuel water separator filter, checked the ASV (no issues there), and replaced the ignition coil.

After re-installing the carb onto the engine and priming the fuel water separator, she fired up as good or better than it ever had.

I had it hooked to a hose in my driveway which was fed into a trashcan full of water, and while it was running in the driveway, I noticed some white smoke coming from the starboard side exhaust manifold where the manifold is attached to the engine block...it was bubbling a bit along the gasket edge. I'm not sure if this would have contributed to my engine surging issues or not, but I'm sure it's not a good thing to have happening. It also seems that it may have been leaking a bit from there for some time as the spark plug under it is all rusted as well.

I'm thinking at a minimum I need to replace the gaskets, but I'm also now concerned about the manifold. Could it be cracked? Too old/rusted out?

The red arrows and circle are trying to highlight where the bubbling was coming from. The view from the top shows the area where the smoke was rising from.

Keno - thanks! I'm assuming my rebuild went well on the Edelbrock but I haven't had a chance to put it under load yet...just ran on the hose in my driveway a few minutes.

I'm really debating taking a shot at the gasket replacement for the manifolds, but I'm slightly concerned about something I noticed while running in the driveway.

I was feeding the boat water from a trashcan I'd filled full to ensure it had plenty to draw from and was also filling it at the same time from my hose. During my test run after the carb rebuild and after noticing that steam coming from the manifold/block gasket, my wife alerted me that there was "white smoke" coming from the exhaust from the stern of the boat. I hopped out to look and it was either steam or smoke...fairly heavy. I immediately shut the boat down.

Could I have burnt up my impeller? Haven't had a chance to check, but I replaced the impeller last spring and it's only got about 40 hours on it. Could the steam be something tied to the leaking gasket?

Yikes...it definitely did not draw 10-15 gallons of water over the few minutes it was running... what is the smoke because it wasn’t getting enough water? Maybe pulled 5 gallons out of the trashcan over the time it was running. Probably going to need to replace my impeller now. Could I have done any other damage?

Wonder why it wouldn't have been drawing water into the engine with my setup this time. It's worked fine for me in the past a couple times...Before though, I hooked directly to the hose but had concerns about whether or not it was getting enough water which is why i moved to a trashcan filled up so that I could see how much water it was actually drawing in.

Any other reasons potentially for that white smoke/steam?

I added Seafoam to my gas tank...would that cause it to smoke by chance? Could something from the carb cleaning or new fuel water separator filter affect it any? The new coil?

I'm searching here. I'll have to open up the pump and check the impeller this weekend. That should be telling for me.

Keno - the trashcan was on the ground, but it was rather tall...it was probably around the same level as the bottom of the boat? I'll try the bucket inside the boat next time!

Also, I'm hoping I'm nearing the end of my issues. While I was having some fun trying to diagnose and solve the problem myself, while also learning more about the workings of the engine and components, I wanted more to be on the water! So, I dropped the boat off at my mechanic and he told me the smoking was coming from a leak on my starboard valve cover. The gasket had run its course and needed replaced. To get to the VC off, they removed the manifold and replaced those gaskets as well in the process. Since they were doing it for one side, I had them replace the port side gaskets as well as a preventative maintenance move.

While they had the boat, I also had them do a compression check and was told everything looked good there! I don't have the numbers on the tests though, but I'll try to grab that data.

Also was told my spark plugs needed changed out so went ahead and had those replaced as well.

All in all...sounds like she just needed a tuneup of sorts and to get that carb cleaned up. I should get it back on Monday and will take it for a spin to make sure she runs well again! Excited to get back on the lake!