1988 120 VRO bogging down...

Hey all,
(I'm not the owner or user...but am helping the owner)
1988 120 VRO. Has run great for 3 years. About 1 month ago owner launches it, it starts ok, then dies. Can't get it started. On a hunch, I checked for water in fuel...almost a full gallon of water in the tank! Take it out for a test drive and although it now ran good again, every now and then it would slow down on it's own as if it were running out of gas. I would pump the primer bulb when this happened with no change. Assumed water was still floating around in gas, so we then brought the boat home, completely drained the fuel and refilled. (Also added correct mixture of oil as the VRO has been bypassed).
Thinking the problem was fixed, he then took it out for a family day. He said it would run great sometimes, but was still bogging down. He changed the plugs and said that fixed it temporarily (?) but by the end of the day was doing it again...bogging down. He did not try the fuel bulb test while running but he said the bulb is staying inflated, not going flat or anything.
We ordered the VRO FUEL ONLY fuel pump, and installed that along with a new fuel filter and new hoses just to be sure. It started and ran fine in the driveway, so I sent him on his way.
He just returned from a fishing trip and he said the boat would never plane out and he only got up to 18 mph at the most. (Usually this is a 32 mph boat). And said it was running rough during this time, but was intermittent but never did run well.

This has got me stumped. I physically saw more than a full gallon of water come out of the tank that first day. Seems it is a multi-problem now. It has new fuel pump, hoses, fuel+oil, and spark plugs.

I told him we were now going to start with the basics. I plan on doing a compression test and a spark test.

If the compression and spark are ok...would any of you suspect the carbs need to be cleaned or is there anything else obvious to check? he's ready to sell it. I'm getting tired of working on it for free.

Randy

try a satellite gas tank, with 50:1 fuel/oil, and bypass the boat fuel. see if it still slows down

If you ran enough water through the engine to make it bog down, I would suspect that the carb bowls are full of water. I would recommend dissasembly & cleaning of the carbs.

Disconnect fuel line at motor, check/clean/replace filter. Pull the bowl plugs, strait in is the main jet, unscrew it, clean it. Spray carb cleaner with straw in empty bowl to flush it out, let drain and repeat, this time put bowl plug back in and try to keep cleaner in bowl. Let it soak. Repeat if goop comes out. Connect fuel line, pump bulb with bowl plugs out, flush with fuel. Install main jets, bowl plug and pump the bulb until hard, air will purge from bowl vent. Don't start a fire. Start motor on hose, let it warm up. With motor running and covers off spray carb cleaner with no straw around carb bases and intake manifold, not in carb. If any gets sucked in rpms will change and indicates air leak, if so rebuild with new kit. Close it up and try it again on the water, if it improves do a Sea Foam job, follow directions on can, expect lots of smoke. No improvement, rebuild carbs with new kit.

Did you ever get the problem fixed I too have the same problem. dirty carbs?? air leak?? what was it????

Ok, here is an update to the boat. I pretty much did everything mentioned in the previous posts. I started with the compression check. All 4 cylinders were right at 80 lbs. (My guauge always registers about 20% low, so I'm guessing around 100 lbs. actual) anyway, they were all pretty much exactly the same. I then checked the spark with a "mr sparky" device. Fat blue spark jumps 1/4 inch on all 4 cranking. We then took the 4 carbs apart...all were extremely clean, no debris, no dirt, nothing clogged up. removed each main jet, no clogs anywhere, blew out all passages and put back on the engine. Started it back up and even in the driveway we could tell there was a miss. I have an inductive tachometer that just clamps onto the spark plug wire and registers rpms, and the upper left cylinder (looking at it from the back) registered no rpms...yet sparks when I put it back on the mr. sparky unit. A few minutes later, that cylinder came alive and the motor seemed to be running great, and I showed "rpms" on every cylinder with my inductive tach pickup unit. A few minutes later we could hear a miss every now and then and found that the upper RIGHT cylinder would register rpm's but would drop out every now and then and show no rpm's for second or two. This continued throughout our testing. In the meantime, each and every time we hook up the 4 spark plug wires to the mr sparky unit (board with 4 nails, and a ground, etc.) it shows spark ALWAYS.
Can the spark be going away on 1 or 2 cylinders like this under minimal load like that? We replaced the power pack May of 2008, and if I remember correctly...it was pretty much the same symptoms, except that when doing the mr sparky test it clearly showed 1 not sparking always, and sometimes 2 cylinders not sparking.

Anyone else agree or think it's the power pack?

Frustrated in Salt Lake. Tired of working on this project for free. My take in the deal is that I am his right hand fishing partner...but it's already not worth it!

Please reply if anyone has any other ideas! Thanks!

Randy

Did you try to switch the plugs?
Might be a faulty No 1 plug.

Thanks for the quick reply! Yes, we did switch plugs. We actually had another brand new set on hand and put them all in, with absolutely no change. I also switched out the spark plug wires on the two cylinders that seem affected, with no change.

According to my inductive tachometer pickup unit, the two upper cylinders would just come and go randomly. The two lower cylinders stayed consistent showing rpm's (spark) at all times.

We also thought possibly a coil was bad, until the 2nd cylinder started acting up as described. At which point I started thinking the power pak was bad again.

The one item that I don't like, is that if we turn the motor off completely and hook up all 4 plug wires to the "Mr. Sparky" test unit that I have...it shows a strong spark on ALL 4 cylinders. Only when it's running does it show those cylinders not getting spark according to my tachometer pickup device, and you can also hear the miss in the motor when it occurs.

Power Pak? $139 on line.

Have you tried switching the coils to see if the problem "moves"?

No, we haven't tried switching the coils. Had it been just one cylinder giving us the issue, I would have tried that, but there are two cylinders that sporadically don't spark...I figured the odds of 2 coils going out at once are pretty slim. However, I did loosen, clean, and tighten the coil bolts, making sure they are grounded good, etc.

Do the power paks generally only last 2.5 years? That's what's got me bugged. We just replaced his power pak May 2008.

Even though the odds of two coils going is slim, it is still possible. Nothing is better than ruling it out. And it is easier than pulling the flywheel.
The only worse troubleshooting dilema is replacing a bad part with another bad part.

Update: Ok, so when I last posted, using an inductive RPM pickup lead, we determined that the upper left and upper right cylinders had no spark while running sometimes (would kick in and out occasionally, registering RPM's when the inductive pickup was attached). The lower two always had fire.
I thought it was the power pack, but some above on this thread told me to try switching the coils. So I put both upper coils on both lower cylinders, and I couldn't believe it but now the lower cylinders are the ones having no spark...indicating that the coils have gone. (2 of them).

On the surface, it seems I've found the problem...buy 2 coils. I can't hardly believe this. I am almost 100% sure that if I buy the two coils and put them on, the problem will still be there.

We are tired of "trying" stuff on this boat. We want to just fix it and start using it again. I'd rather have him buy extra stuff to guarantee that we fix the problem.

In your experience, anyone, could this still be the powerpack, or will it indeed just be the coils, or should I have him buy both the powerpack AND (all 4) coils?

Thanks.
This is extremely frustrating...especially given the fact that the initial problem was WATER IN THE FUEL!!!!!


Randy

I'd buy the two coils.

Ok, I give up. Please help.
See above for long drawn out story. We bought a NEW POWER PACK (this motor only has ONE), and FOUR NEW COILS. I also replaced the fuel filter with a new one AGAIN.
Took the boat out (I was not on the boat again) and owner reports back that it only goes 22 mph @ 3400 RPM's. Once it gets above that the engine starts shaking with a severe miss in the motor. He says it idles perfectly and seems smooth up to 22 mph, but lacks the power it used to.
This used to be a 33 mph boat @4500 RPM's or greater.

So, at this point we have a New Non VRO fuel pump, new plugs, new power pack, 4 new coils, new fuel filter, freshly filled gas tank after flushing it...removed and disassembled and checked all 4 carbs, they were clean, and all because the problem started out with water in the fuel?
He says that pumping the bulb does no good, and it doesn't seem like a fuel problem anymore anyway, he says it's a sever misfire.

HELP!!!!!

What else do I even check for?
In the driveway, it has compression, spark and fuel. to all cylinders.

PLEASE RePLY!!!!!

Thanks.

Here are some ideas: They are not CHampion plugs...going to have him buy some new CHAMPION plugs. Also the 4 coil wires are not new, going to have him try replacing those. After that, I'm going to see if I can go to the lake with him and try undoing the primary wire from each coil one at a time to see if I can detect a cylinder that is missing...but if it is...what can it be? Says the tach is working so I'm not susupectihng the stator...

check the timer base wires for a short to ground. the timer base plugs into the cd box. look for the connector and unplug it. (wires come from under the flywheel, port side, under the stator. hook one end of an ohm meter to ground, then probe the wire connector that goes under the flywheel (5-6 terminals in the connector) one at a time, if any of those show continuity to ground, then look for a bare wire, if none, then replace the timer base. you must reset the timing after replacing the base.

Problem solved FINALLY!!! Decided to go back to basics and had him purchae 4 new CHAMPION spark plugs (He had replaced them with an off brand earlier)
and told him to buy 4 new plug wires also. The dealer had only 2 wires so we went with that. The old plugs were gapped at .045...which might have been the
most recent issue actually...
Anyway, what started out as water in the fuel on July 4th, we ended up doing the following:
1. Drain, clean and refill tank (premixed...VRO was disconnected years ago)
2. New Non-VRO fuel pump (the expensive one)
3. New fuel filter and hoses
4. New Power Pack
5. 4 new coils
6. New set of CHAMPION plugs gapped at .030
7. 2 new spark plug wires.

All is good now! 33 mph @ 4500 rpms, and it runs better than it ever has!
Thanks for all your help!

Glad you got it fixed. By the way that engine is supposed to jump a 7/16" air gap. Champion plugs are always recommened for that engine.