'97 Yamaha problems

My 1997 150 hp Saltwater Yamaha will not get on plane.

Unit starts just fine, but no power.

I checked the plugs at idle and have no spark on the upper top left cylinder and the bottom right cylinder. Should these plugs have spark?

I changed the coil from the top left cylinder with the one from the middle cylinder and still have no spark.

Do I need to check something else or is the problem the electronic module?
Can these units be checked?

Trying to eliminate stuff one at a time.

Any suggestions will be appreciated

Jerry

Re: '97 Yamaha problems

post the full model number.
need to know because some of these models incorporate CCS.
At about 500 RPM all six spark, from about 550 to about 2000 #5 DOES not spark, from about 850 to 2000 #2 does NOT spark.

Also explain the power problem you're having with more detail, history of the problem, when the last time the motor was running right, etc. This always helps because we can only offer help to the information we read.

Re: '97 Yamaha problems

The model # is s150tlrw.

The boat sank in dec. 2006 and was partially under water for about 12 hours, then pickled and seafoamed to death. Carbs rebuilt, oil drained/cleaned, gas tank drained/cleaned, new plugs, new impeller/lower unit greased.

The engine ran fine from Jan. 2007 to march 2008, then developed an intermitant problem with the engine going from 5000(est.) rpm to 500(est.)rpm. If I pulled the throttle down to the idle the engine would continue to idle fine. This would last for a short time and then run fine at full throttle for hours.

This problem continued to get worse until october 2008 where the intermitant problem became always a problem running on less than all the cylinders and could not get on plane. Do not have a tach so do not know for sure rpm but maybe 2500 or so.

Let me know if any more info is needed.

jerry

My striper fishing season is about in the tank, but would like to fish next year.

Re: '97 Yamaha problems

Without a yamaha gauge, it's tough to tell exactly what is happening. I'm guessing the motor is going into a reduction mode.

perform some visuals when the problem occurs.
1) is the oil tank on the side of the motor close to empty when the motor drops rpm's. could be a slow remote to engine oil transfer, clogged filter on remote oil tank.
2) are the heads too hot to touch. engine overheating. could be closed themostats.

Hopefully Rodbolt will chime in.

BTW, your motor S150TLRW is a 1998.

Re: '97 Yamaha problems

Sorry to say that the oil pump in the remote tank no longer works(even with the switch on the engine) and needs to be repaired, so the only oil I have right now is in the reserve tank under the cowling, the alarm sounds when it starts getting low. The engine ran fine for about 6 months with only the reserve tank.

I now believe that once all that wiring gets real wet it is only a matter of time before some/lots of corrosion will start.

I did have a shade tree auto mechanic(25 yrs. exp.) check the temp about 8 months ago with some kind of temp measuring device, don't remember what the readings were but he said it looked ok to him...he is not a marine mechanic and tells me that.

Re: '97 Yamaha problems

how old is the fuel pump?

Re: '97 Yamaha problems

On a boat it is almost always a bad ground that causes electrical problems

Re: '97 Yamaha problems

I bought the engine used in 1994. As far as I know the fuel pumps are original.

Did have a problem about a year and a half ago. The engine would almost stop running, then after a while it would take off again, after some trial and error, the guy who does the maintenance, noticed that the primer bulb was sucked flat. Took a while for it to release the pressure. Replaced the primer bulb assembly and the problem went away.

I do have an in-line fuel/water separator installed. Have had problems in the past with water in the fuel. Think I have partially fixed the problem.

Guess I should just take up golf.

Re: '97 Yamaha problems

Sorry about that, I bought it used in 2006

Re: '97 Yamaha problems

what you actually have is a 1998 20" shaft carburated engine.
this is a smart motor so you only have 2 pulser coils but you do have a crnk position sensor.
you will need a spark tester with 6 inputs set at 7/16th to accuratly measure the ign system.
simply pulling a wire while running doesnt tell much.
do a forum serch for homemade sprk testers.
to start check spark on all 6.
if all six spark then test compression.
if compression is good fix the fuel system.
if spark fails test the CDI inputs,pulser coils and charge coils, and the crank position sensor output.
as this boat sank carefully check all connections for corrosion.
if you remove the screen assy from the engine oil tank its imperative to retrieve and replace the seal on the filter.
always completly drain the engine tank BEFORE removing the screen assy or you may dump trash down the oil pump intake line damaging the pump and causing an engine failure.
while ground failures happen they are not the sole cause of electrical failures.
for your transfer, at the remote oil tank check for 12V between the brown pump wire and the engine block with the key on and the transfer switch activated.
if you have 12v then do a continuity test of voltage drop test between the blue pump wire and the engine block with the switch activated.
just behind the 10 pin main harness connector is a splice where the oil pump wire changes from yellow to brown and can fail.
sounds like you have allowed a tremendous amount of neglect and couple that with a shade tree tech working on it you may have multiple issues going on.
my advice would be find a professional to carefully inspect and test this motor for futher service.
but trust me, you need to find someone with the correct tools and knowledge to work with the 2.6L SMART ign system as well as a working knowledge of the PBS system found on the post 95 and up v6 yamaha's.

Re: '97 Yamaha problems

Thanks for all the suggestions.

Guess I am in way over our heads.

do not know what CCS or PBS system is. but gather that I have an engine that has a bunch of built in diagnostics that can cause the engine to not run correctly because it is sensing a problem?

The problem may be in the oil tank/s or some other places.

I will check to items you suggested.