Yamaha 150 HPDI 2001 Troubles

[TomKat87]

here goes...boat starts right up at home and right at the dock, but after running the boat for app. 25-30 min. boat cranks and almost starts, but will not unless I can manage to slip it into gear enough to it seems give it gas and it sputters and within 10 seconds is running normal but this isn't always effective and my last trip out I pulled the cover out of desperation and depressed the shifter switch several times and I believe it fired up but then it ran like cylinders were missing, like it does when the shifter switch is going bad. Only way clear that is to turn off the motor and try again. Finally started on all cylinders and ran 10 miles home,running strong but I knew not to shut it off. Get home hook up the muffs and it fires right up, strong.

Note, boat has been worked on by reputable certified Yamaha Mech. who recently after going through fuel and electrical systems found clogged fuel filters to be the culprit of abrupt power loss when throttling up. That problem went away. The filters where not too bad I saw them. Right prior to this I took it to a bad Mechanic who said my shifter switch was bad as well as my throttle and shifter cables so he replaced them. I have since found in the engine tray the throttle cable cotter pin, and on the other side of the engine, another small cotter pin in the bottom of the tray that came from a small nylon ball/snap assy. that is attached to a linkage. I have also moved that as my wife cranked the engine and once it did help start but gas/oil did spray out the exhaust when it did. New shift switch to be here today cause that thing has given me trouble from the first week I bought the boat and Im thinking that because even when the boat does finally start, it exhibites the symptoms of a faulty switch at times now. I need to resolve this.

Why start right up, run strong, reverse,foward, fast,slow, run for 5,10,15 minuts,turn off and it starts right up, but go 25 or 30 min+ and its as I said, almost, but seems to need throttle or something..Thanks this is so long winded..breaking down sux!

[rodbolt17]

do you understand why the shift switch is there,what it does and how to test it?

[TomKat87]

Well I thought I did but I must say Im a bit confused at this point as to what it does. Please if you can make it clear it would help. I guess I thought that when the boat is in neutral and the micro switch tab is pressed down that the boat would start then and only then, so it would not start in gear. I don't understand why, how, or if it affects the firing to certain plugs But I assume it does. Do I have that right?

[TomKat87]

Also, I do not know how to test but I did read something about disconnecting the switch and using a paper clip to by pass but it am reluctant to stick a paper clip bent like a horseshoe in the connector but is that correct? Thanks again.

[rodbolt17]

that switch has NOTHING to do with engine starting.

the shift position switch tells the ECU whether the engine is in a gear position or in neutral.

if the ECU sees an in gear position AND it sees a crank signal it will lock the RPM to about 2200 RPM.

if the ECU "sees" its in neutral it will shut off cylinders 2 and 3,if RPM increases above about 1500 RPM and the ECU still "sees" N it shuts off cylinders 2,3,5 and 6.

switch should read open circuit in N and closed in either gear position.
can be watched on the laptop.

[TomKat87]

10/4 rodbolt17, thank you! Ill need to digest that a little bit and see how that may apply to my to 2 intermittent symptoms, reduction in cylinders upon starting if it starts, and out right failure to start unless I can manage to slip it in gear as it barley sputters on the verge of starting. My new switch, a 44 dollar gamble will not be here till Monday and it seems I need to launch and ride for 30 minutes to bring this on. I do not have a lap top to test as you suggested. But one last question please sir...based on that info, it seems like for what ever reason, the ECU may be shutting down cylinders 2,3,5 and 6 or a variation upon a dead start, intermittently. If that's the case, how could that happen? *** FED EX just now dropped of the switch. I will install and pray and then river test tomorrow and report back. rodbolt17, thanks again it seems to me the ECU is manipulating those cylinders when it should not for what ever reason. Hope its this switch..will report back

[TomKat87]

ok pulled out old switch and ohms tested good on bench, new one installed waiting for Sun. morn now to test boat in river.

[rodbolt17]

the ECU is only going to cut cylinders based on inputs,or lack of, from the switch.

you most likely now own a spare shift position switch.

that's why the laptop is so easy, it keeps me from chasing ghosts.

[TomKat87]

I want the lap top, how much and where can I buy one with software?

[TomKat87]

one other thing then on the lap top, when the last certified Yamaha mechanic worked on my engine and hooked it up to there lap top there was only ***xs every parameter there should be numerical data, they showed me the print out and said this happens from time to time. I trust them completely so can that lap top even be utilized on my engine anyway? I think they said no, it was bad. Im wingin this cause I cant afford another 1800 in cash. Thanks

[rodbolt17]

if the dealership is using the newest version 2.0 or later, your printout will have about five pages, mostly commas.
if the are saving it to a spreadsheet type program such as Excel there are less commas.
it still works and you can watch the data live as the switch goes from on to off everytime the shifter is moved.

BRP diagnostics still makes the version 1.33.

[TomKat87]

Ok, back off the water after app. 25 miles and maybe 4 hrs on engine with many on/off start from dead start. Engine still exhibited failure to start app 2 out of 10 times, a big improvement and every time it did start, all cylinders fired and that engine when running fine is unbelievable, cobia 194 comes out of the pocket like a police interceptor...but I still those few times had to pump ball, ( never ever have to this ) and it still sometimes would not get hard, but some times it would and even if it did the engine would not start unless I put it in neutral ( I forgot it could do this as I never have had to after 12 years owning boat) and push throttle to wall, back,forth, fires up rough for 5 sec, then run like a scalded monkey. Came home, replaced fuel/water filter right near tank under deck cause Im thinkin pin hole in filter, drain gas in jar, looks really good except for small few particales, never smelled gas one bit around filter but I had an extra one so I put in the new one. So... the ball will not get totally hard at all now and that clear gas filter app 5 inches long on the left side of the engine bubbles and sometimes fills near the top but right now 3/4 full when I pump the ball with out the engine running and still the ball will not get hard as it used to. Balls in good shape, no gas fumes, no leaking fuel to see or smell anywhere. I suspect the last symptom here is a fuel issue in pressure or delivery at intermittent intervals upon a dead start. Any thoughts?? thanks