Help! My Yamaha HPDI outboard has a mystery issue

[hokiepoq]

and vacation starts tomorrow! I have a 2001 200hp HPDI Yamaha on my Proline. It did sit for about 9 months before I got it in the water this year, so that may have something to do with it. When I took it out, the boat didn't work so well because I have a persistent throttle-body gum up problem because of the saltwater spray it gets while on the bracket on the boat. I've since rigged a few things that I think will solve that problem. The mechanic (who has been very good) ungummed the thing and it worked great. I took it out and it ran perfectly. I took it out the next day and, low and behold, it would only get up to 2500rpm that was with the throttle all the way down. Well, I took it back to the mechanic and, after sitting waiting to be looked at for 8 days, he looked at it and said he couldn't find anything wrong with it. He started and ran it several times (one when I was one the phone) and it ran perfect. He said he hooked it up to a "dyno" and all things looked great. His only speculative suggestion would be to be sure the primer bulb was nice and tight before starting it up. I took it out today and it ran perfectly on a 4 or so mile run out. I stopped the engine for a few minutes. Then it went right back to the 2500rpm max! I turned it off, primed the bulb, same thing. No binding in the unit, it just seemed to only run no more than 2500rpm no matter how I tried to throttle it. I know if I take it back in to the mechanic it will work fine. The filters were all recently changed and he said they all looked good. I'm at a loss and am hoping to use it extensively during vacation which starts tomorrow! Any suggestions? I would REALLY appreciate it!

 

[hokiepoq]

Re: Help! My Yamaha HPDI outboard has a mystery issue

Well, it looks like either my problem stumped people or, judging from looking at other posts, people may feel like troubleshooting this has already been addressed. I know the VST filter keeps coming up and I changed that last year. Anyway, I was encouraged by the one expert poster who said that HPDI's are not that hard to work on (the non-hi-tech part that is) but you do need the right tools. Can someone suggest the minimum tools required to maintain and troubleshoot the engine? I'm not talking about rebuilding the block or anything, just the most common issues. The engine is a 2001, but it only has 175 hours on it. I'm going to call the mechanic as soon as they open to see what he has to say about it. The worst case scenario is that I take it on vacation this morning and run it as low rpm - makes it more of a happy hour cruiser than a fishing boat, but at least it gets us on the water.

 

[hokiepoq]

Re: Help! My Yamaha HPDI outboard has a mystery issue

OK, looks like the mystery may be solved. Went to the mechanic this morning and, after being very perplexed, he said "aha! I know what it is!" Turns out that it is (most likely) the throttle position sensor. Sometimes it doesn't "sense" that it's supposed to fire on all 6 cylinders so it only fires 4 thinking it is still in neutral. He adjusted it and said it should work most of the time and he will order a new one. At least I can go on vacation with some hope of it running ok. People can file this one into their knowledge banks. Still looking for basic suggestions for tools to help maintain the engine and troubleshoot basic problems.

On to vacation!

 

[rodbolt]

Re: Help! My Yamaha HPDI outboard has a mystery issue

find a real tech BEFORE you smoke a piston at worst or at best spend a lot of moiney.
the TPS has ABSOLUTLY nothing to do with dropping cylinders in N or picking them up when shifted into gear.
if your tech doesnt have at least certs on the wall from Yamaha for fuel and electrical please find one who at least knows how the system works.
yours appearently does not.
the shift position switch is located on the shift slide down low on the stbd side of the engine.

 

[tonynorie]

Re: Help! My Yamaha HPDI outboard has a mystery issue

I learned a long while ago to defer to someone as knowledgeable as Rodbolt when it comes to Yamaha motors and I certainly don't want to suggest that I am any kind of authority.

Having said that, I do have the 200hpdi (2001 year) and I try to learn as much about it's operation as practicable and when I read your original post what popped in to my mind was this: doesn't the engine drop rpm's as a safeguard when the engine oil tank level drops below a certain threshold? Has that been checked out?

As far as recommendations for tools and methods to maintain your engine, I would suggest you invest in a model specific service manual. You'll read a lot of what you'll need to know about the maintenance you can perform your self, as well as intervals for those procedures and whether or not special tools are required and the degree of difficulty involved. I'd also suggest that you pull the cowling and familiarize yourself with the various components under the 'hood' and while you're there, look for any signs of trouble, including leaking fluids, loose connections and bolts, deteriorating hoses, etc.

Good luck and I hope you get to use your boat while you're on vacation.

 

[rodbolt]

Re: Help! My Yamaha HPDI outboard has a mystery issue

if it was going into RPM reduction you should get an audible, a quick check of the audible on this engine is simply pull the stop lanyard and crank the engine, you should get an alarm while cranking.

 

[hokiepoq]

Re: Help! My Yamaha HPDI outboard has a mystery issue

Rodbolt, a little harsh on your comments regarding my mechanic. I was probably not completely accurate in what he said was wrong with the engine as he didn't write it down. Whatever he adjusted as a temporary fix did fix the problem. I've been running it every day since and it has worked great. And he did check the oil level and test the alarm while troubleshooting the problem Monday morning (I was there watching him). He's a great guy and has done right by me for years.

Tony, thanks for the advice on what to get for the engine. I got manuals for my other outboards, I don't know why I didn't think about that for this one. Great place to start. Thanks!

 

[rodbolt]

Re: Help! My Yamaha HPDI outboard has a mystery issue

that engine has multiple fuel and ign control switchs and sensors.
if your not positive what does what and how it affects fuel and spark you should not tinker much with it.
I have an F115 2007 model that went to a shop with poorly trained techs, they reset rhe cam timing for some reason and now it has 4 bent intake valves.
when I looked at it yesterday the intake cam was 2 coggs off.
my bore scope took some pretty pictures of the half moon smacked into the piston crown.
someone is getting ready to have their general business liability insurance tested.
so I try not to be harsh but I am telling you that untrained,poorly trained or techs that only have a seloc manual can blow powerheads and do with amazing regularity.
always look for the yamaha school certificates on the wall. if all there is is a 5 star move along nothing there to see.

 

[mbyrne]

Re: Help! My Yamaha HPDI outboard has a mystery issue

hi guys,
Im have a very similar problem with my 2005 175hpdi outboard (saltwater)
It have nearly exactly the same issues as hokiepoq. the only difference is my
boat is still in the shop and my mechanic still hasn't any idea what the problem is. (p.s my mechanic is a fully licensed yami mechanic in a yami workshop )
my problem is, she would be running fine and then just drop of to about 2500rpm and will not rev any higher. then, when i turn the engine off and leave her for a few mins and start her up again, she runs great for about 2-5mins and the same problem occurs again. ive had her on the OBD and its shows up no codes or anything out of the ordinary. when shes in the w/shop she runs great.... ARG!!!! its a real annoying problem and any and all help would be really appriceated.( P.s i'm a motor mechanic aswell, which is extra annoying. not being able to fix it )
Thanks for reading and postin
mark

 

[rodbolt]

Re: Help! My Yamaha HPDI outboard has a mystery issue

what is the fuel rail pressure on both the medium pressure and high pressure lines at the TIME of failure.
wont see it on a flusher.
there is no such thing as a "licensed" yamaha tech.
however I do get accused of having a license to steal .
there are training certificates that say a tech has met the MINIMUM standards of learning.
5 star is a self paced video course and is for entry level only.
look for actual school certs for at least fuel and electrical on the dealers wall.