Engine Starting Problems

[RayJake]

I've got a 1994 Yamaha 150 TXRT on my Grady White 208 Adventure. Neither the boat nor the engine has been out much this year. It has about 550 hours on it.

I was able to get it started about two months ago, but it wouldn't run for long and I ran the batteries down trying to get it started. (Fortunately, I was still at tthe dock.)

Anyway, a friend I went to the marina today with recharged batteries and attempted to start it, but we were unsuccessful. (I brought him along because he's got much more experience with outboards than I do.)

We had an induction timing light and checked for power to the cylinders. The port plug wires were getting power, but the starboard plug wires did not get power. We were unable to see anything obviously wrong with the wiring and connections.


Any ideas or suggestions to help me :?:

 

[LI Grady]

If one side isn't getting spark then I'd start there.

Get a volt meter and a manual for the motor and starting from the battery follow the voltage from there all the way to the plug or in this case where the volatage dead ends.

Could be a bad coil, connection, etc.

 

[BobP]

I would think the motor should still start on 3 cylinders, won't rev up or have any power, but should still start and run IMHO.

 

[Grog]

Most meters will not like the 30,000 volts coming off the coil.

The carbs were primed?

Were you using the choke? Was it working?

On my engines, a carb rebuild helped the starting A LOT. If they're running lean it's harder to start them.

Was the motor kicking at all?

 

[LI Grady]

Grog

I'm new to outboards so forgive my ingnorance. I've check power to the coil on my inboards in the past without any problems. Are outboards different?

Also perhaps I was being to general.

 

[Grog]

I wasn't trying to be condensending but there it a lot of voltage coming off the secondary side of a coil. Meters are generally rated for 1000V, I wouldn't use a meter to check the secondary side which sees at least 30,000 volts (or should see). A guy where I used to work used a meter on an arc light that wasn't working, guess what happened.

Outboards are generally the same as inboards as far spark goes. They are generally more finiky to start when cold than your typical inboard. They don't have an accelerator pump like 4 strokes so all fuel has to be sucked in by the engine.

 

[LI Grady]

Grog

It never occurred to me to take your comment as condensending. You've given me and others a lot of very good advice and I have never seen you respond in any way other then courteous.

If I can pick your brain a bit, in your opinion what is the best/easiest way to check the secondary side? I always get nervous about pulling the plug and arcing it as someone hits the key. Do those transparent add ons that allow you to see the spark work? I realize this only tells you that you have spark not the quality of it.

I'm dealing with '90 vintage Yamahas so I'm trying to amass as much info/knowledge as I can since I will more then likely experiance a few of these issues myself.

 

[choogenboom]

couple thoughts:
1) just because the timing light blinked does not mean a spark occurred. The inductive pickup tells you current flowed through the spark wire but it can't tell you if the plug is fouled (in which case no spark) or not.
2) Agree with Bobp - assuming you have 3 cyclinders sparking and fuel then it should still run on 3 cylinders albeit very poorly
3) do you smell gas coming out the exhaust while cranking? Have you pulled a plug and is it wet with fuel or dry?
4) One CDI module controls each of the 6 coils, so seems odd that three of the 6 would go out all at the same time. All six dead (bad CDI module) makes sense, one dead (bad coil) makes sense but 3?
5) the voltage on the secondary can't be seen with any volt meter. Voltage levels aside, voltmeters can meaure DC volts or low frequency AC (ie 60 Hz AC). The voltage on the coil secondary looks like a few millisecond pulse going to 30-40 Kv.
6) Your timing light with inductive pickup is a good tool for the job, but there is no substitute for pulling the plug, cranking the engine and seeing a nice fat blue spark.
7) whats in your fuel tank? E10 ethanol blend? What fuel level was the boat stored with? Have you drained your fuel filter into a container? What came out?

 

[Grog]

However crude it is I like the screwdriver in the spark plug wire jumping to ground method, you see the spark. Be sure there isn't any gas puddled anywhere or a lot of vapor.

My timing light pulses (slowly) even when the pick-up is off the wire but that doesn't explain why one side pulses and the other doesn't. Is it kicking at all or just cranking? Have you opened the carb drains to see if there's fuel in there? Did you check the water separating fuel filter?

You can try hooking up a small tank of new gas, draining the carbs, filling with new and see what happens.

Don't crank them too long, the starter motor will get quite hot and burn itself up.

 

[choogenboom]

Even if you see a spark jump from the screwdriver to ground that does not guarantee your spark plug is sparking. If your plugs are fouled they will not spark. You need an airgap for a spark and a fouled plug has no air gap. Its also harder for a spark to jump across an air gap when that air is under pressure as it is during the compression cycle. So even if you see a weak spark at ambient air pressure that does not mean the plug will spark at a typical 100-120 PSI inside the cylinder.

 

[RayJake]

Thank you all for your input.

I'm going to keep going by looking at the spark plugs and the fuel lines/filter/separator next.

I'll print out all of the suggestions here and work on these ideas.

I've tried to steer away from gas with ethanol, but have heard that some stations had it and didn't label their pumps. So I may have had E-10 in the tank. I have used Sta-Bil (red) and Ringfree when filling the tank, though.

Unfortunately, it did sit for a while at about 2/3 to 3/4 full for about three months.

Oh well, it might be time to contribute again the the mechanics economy.


If it's too expensive for repair, does anyone have suggestions on how to convince the wife that I need a new 4-stroke?

 

[JUST-IN-TIME]

sounds like the 2 triggers are shot or Ur in rpm reduction mode
u need a good meter and DVA to test the things under the flywheel
you can test the coils primary and secondary leads in ohms
if you have the orange spark plug boots, i have seen those go bad one after another, that is what the secondary lead test will show ya
if you run the starter more than 10 seconds, u might overheat it

i do not have a manual for that one, but i know the colors and what to look for

 

[JUST-IN-TIME]

sounds like the 2 triggers are shot or Ur in rpm reduction mode
u need a good meter and DVA to test the things under the flywheel
you can test the coils primary and secondary leads in ohms
if you have the orange spark plug boots, i have seen those go bad one after another, that is what the secondary lead test will show ya
if you run the starter more than 10 seconds, u might overheat it

i do not have a manual for that one, but i know the colors and what to look for

 

[seasick]

First of all, I think that motor is not carbed. If it is the OX66, TXRY, it is injected. It could be a pump issue. Try to start the motor and then pull a few plugs. They should be a tad wet from raw fuel. (make sure the plugs are not fouled also) If one side is all dry and the other is wet, you have a fuel deliverly issue. If all are wet, you probably have a spark issue. I have to look at the parts diagrams to see what is common to 3 cyls.

 

[seasick]

There are two fuel pumps, one for the port cyls and one for the starboard side. I can't say for sure if that is the problem but it's possible.
Fuel pump is part no 6E5-24410-10-00 ( I think)

 

[choogenboom]

If the model number is as you stated in your opening post, a 150TXRT, then its a 1995, not a 1994. Scroll to the bottom of this page to see how to interpret a Yamaha model number http://www.boats.net/parts/search/Yamah ... parts.html

The 1995 150TXRT is carburated. See this page for the exploded view of the carburators. http://www.boats.net/parts/search/Yamah ... parts.html

See this page for the intake showing the carbs as a unit. http://www.boats.net/parts/search/Yamah ... parts.html

There are indeed two fuel pumps - see this page
http://www.boats.net/parts/search/Yamah ... parts.html but they are not each dedicated to port and starboard. This engine has 3 x 2 barrel carburators. Both fuel pumps are plumbed in parallel to the fuel feed line that goes to the three carbs so both would have to fail before the engine would not run at all. Note that my conclusions are drawn from looking at the exploded parts diagram, not from personal experience with this engine. I have however owned and worked on a similar engine (a 1994 250 TXRS) which had 6 x 1 barrel carbs.

My gut tells me you have a fuel delivery problem, possibly related to ethanol, but I would like to hear back from you if the plugs are wet or dry after priming and cranking before jumping to that conclusion. Note that if it is a fuel delivery problem related to ethanol your fix might be as simple as replacing your main fuel filter and the under the hood fuel filter.

Good Luck,
Chris

 

[seasick]

Choogenboom,
My mistake, I read the model incorrectly. In 1998, the SX150 was introduced. That is an injected model.
I would still pull the plugs first though just to see if there seems to be fuel or if they are fouled.