Considering Buying a 2016 AR190, Weird Hesitation / Top Speed Problem on Lake Test HELP!

[TheGrayt1]

Hello all,

I am really close to buyiing a clean 2016 Yamaha AR190 with about 66 hours on the clock. I made about an hour trip to go look at it and water test. The boat started right up but when running it for the first 10 minutes it acted real weird. The boat would kind of hesitate and at WOT would only go 23 mph at 6200 rpm. I killed the enging to go check thge oil and inspect everything and it looked fine. After restarting it it ran perfect and never missed getting up to 40mph and 7600 rpm. The owner said that has heppened before and it is probably old gas with the stabilizer in it. No clue how old the gas is. Has anyone ever experienced this? Should I be concerned or chalk it up to old gas? Also spark plugs and oil are original I believe so it probably needs a full servicing.

Side note, I would be getting the boat and galv trailer for $17kish, is that a good deal?

 

[2kwik4u]

Hello all,

I am really close to buyiing a clean 2016 Yamaha AR190 with about 66 hours on the clock. I made about an hour trip to go look at it and water test. The boat started right up but when running it for the first 10 minutes it acted real weird. The boat would kind of hesitate and at WOT would only go 23 mph at 6200 rpm. I killed the enging to go check thge oil and inspect everything and it looked fine. After restarting it it ran perfect and never missed getting up to 40mph and 7600 rpm. The owner said that has heppened before and it is probably old gas with the stabilizer in it. No clue how old the gas is. Has anyone ever experienced this? Should I be concerned or chalk it up to old gas? Also spark plugs and oil are original I believe so it probably needs a full servicing.

Side note, I would be getting the boat and galv trailer for $17kish, is that a good deal?

$17k-ish is a helluva deal if the rest of the boat is in good condition. I wouldn't let my '17 go for that.

Mine doesn't like to run well if it's been in salt water and then sat for awhile. Sometimes takes a restart or two to clear it and get it back to normal. 7600rpm is right on the nose of how many revs you want. I would suspect some corrosion on the plugs, bad fuel, or general lack of use as the issue. Pulling the plugs and having a look is a pretty quick/easy way to check. While you're in there a compression test is relatively easy to get done as well (Autozone will rent you the tool for free). That will tell alot about the condition of the engine. Combined with a used oil analysis.

Also, I can typically tell if a vehicle has been taken care of with just a general look around. Is it obviously clean and tidy. Are the nooks and crannies well cleaned? Engine bay clean? Is the stuff onboard organized at any level, or is it just thrown about? This same mentality typically follows over into engine maintenance. Do they have any records at all? Does the current owner know how to check the oil?

66hrs on a 2016 is VERY VERY VERY low. To the point I would be more worried about stuff dry rotting and having not been maintained properly than I would wear/tear. I have a shade over 400hrs (I think) on my 2017, and we're a moderate usage family. With that kind of price, it's worth spending a few bucks to have a local shop look it over. If it were me, and the rest of the boat looked to be in good condition, I would put a deposit down contingent on a clean bill of health after a knowledgeable mechanic looks it over and returns favorable results. I would move quickly on that plan, because $17k on that boat means it likely won't be around long.

 

[Julian]

Probably just needs new spark plugs, or you briefly sucked up some weeds? Do a compression test on the engine and if it passes I'd buy it.

 

[TheGrayt1]

Yes, I feel like if the motor was hurt it prob would have never got to full speed and revs. The boat is super clean everywhere else except a small cut in one of the seats from a fish hook but should be an easy repair. I have a compression gauge but did not bring it and the guy is an hour away. If I run a comp test what should it be? Also, would you be concerned that it is original oil and spark plugs? He said they did not change it bc the manual said every 100 hours. Is that true?

Also this is a North Texas boat so no saltwater ever.

 

[Neutron]

Yes, I feel like if the motor was hurt it prob would have never got to full speed and revs. The boat is super clean everywhere else except a small cut in one of the seats from a fish hook but should be an easy repair. I have a compression gauge but did not bring it and the guy is an hour away. If I run a comp test what should it be? Also would you be concerned that it is original oil and spakr plugs? He said they did not change it bc the manual said every 100 hours. Is that true?

Every 100 hours or once a year. Just like oil changed once a year or 100 hours. If the boat was in storage and not used, the plugs and oil should have been changed before it was put in water

 

[TheGrayt1]

Every 100 hours or once a year. Just like oil changed once a year or 100 hours. If the boat was in storage and not used, the plugs and oil should have been changed before it was put in water

That will be the first thing I do if I buy it for sure. I just want to make sure it did not hurt the motor. The oil looked nice and clean though if that matters.

 

[TheGrayt1]

Ok the seller is agreeing to a compression test prior to buying the boat. What should a healthy 1.8l NA motor readings be?

 

[FSH 210 Sport]

Ok the seller is agreeing to a compression test prior to buying the boat. What should a healthy 1.8l NA motor readings be?

Not sure of the number but I’m sure @Neutron has idea, but the readings should be within 10% of each other.

Yes, I feel like if the motor was hurt it prob would have never got to full speed and revs. The boat is super clean everywhere else except a small cut in one of the seats from a fish hook but should be an easy repair. I have a compression gauge but did not bring it and the guy is an hour away. If I run a comp test what should it be? Also, would you be concerned that it is original oil and spark plugs? He said they did not change it bc the manual said every 100 hours. Is that true?

Also this is a North Texas boat so no saltwater ever.

Except you’re supposed to do an oil change at the first 10 hours.

As the others have said, if you get this boat change the oil first thing.

 

[David Martin]

According to my service manual on my 1.8 SX240 the compression should be 110.9 PSI at 68 degrees outside ambient temp. I tested mine at 27 hours on the meter but I cant find my notes ill keep looking!!!!!!I

As for the bad gas going from 23 to 40 Noooooooooo way. Bad gas can cause a performance loss........BUT it will not SELF CORRECT ITS SELF.

Best guess on a 1.8 would lean towards a MAP Mass air flow sensor or a TPS throttle position sensor or Manifold pressure sensor or a Manifold temp sensor or a cam position sensor ALL these sensors feed info to the EMC (computer) and the EMC tells the fuel injectors how much fuel it needs to reach 40MPH. ANYONE of these can kill performance.

Now the random part of the performance change you saw is probably the reason its up for sale..............none of these sensors are all that expensive or hard to test for.............BUT much more costly if the dealer is performing the testing.

 

[David Martin]

Last if the compression checks out and it's a clean well cared for boat, I would purchase............ the performance change does not scare me! Finding a bad sensor if the compression test ok is not that hard..............it's when the sensors test good................then finding the corroded Positive or Negative ground wire on all the sensors>>>>>>>>>>that adds a few hours and (headache for me) to the testing process for sure. I hate corroded wires but one needs to get used to it in the marine environment.

 

[JDRacing]

Just to chime in here--If you want to invest the money (under $35) put some new plugs in it while you're doing the compression check, and, if they will let you, take it out on the water again after doing so. Don't be fooled by the fact that the plugs that come out of there will likely look brand new still. It's not like spark plugs in a car or motorcycle that show obvious signs of wear when they deteriorate--these don't. They just don't work right, create engine misses, and the boat behaves exactly like you're describing, in my recent experience. Put some anti-seize (just a little dab) on the plugs before installing them, and torque to 20 ft-lbs.

If there's no check engine light, that's a clue that maybe the MAP, O2, etc. sensors are ok. Mine (2018 2012X) just behaved exactly like you're describing after sitting for a season without use, except that even though it cleared out, it threw a check engine light on each engine.

Sounds like you're looking at a nice boat at a good price. Put some plugs in it, and if the compression checks out, as others have said, buy it. Then change the oil first thing.

Jeff

 

[Neutron]

Ok the seller is agreeing to a compression test prior to buying the boat. What should a healthy 1.8l NA motor readings be?

With all the plugs out and if you could hold open the throttle plate(which is tough to do on this setup) your readings with a good gauge should be 175psi to 190 but since you cant really open the throttle 150+ would be good and like @FSH 210 Sport says all cylinders should be within 10% variation

 

[David Martin]

WOW..........My dealer service manual was wrong!!!!!! I took readings almost 4 years ago and could not remember so I went with the service manual......Yakes not even close.

I found my notes my top compression was 194 PSI and my low was 187 PSI that a big difference from the service manual 110 PSI. Guess that was a misprint.

 

[Neutron]

WOW..........My dealer service manual was wrong!!!!!! I took readings almost 4 years ago and could not remember so I went with the service manual......Yakes not even close.

I found my notes my top compression was 194 PSI and my low was 187 PSI that a big difference from the service manual 110 PSI. Guess that was a misprint.

2 strokes are 95 to 120 psi some higher. But 4 strokes unless it had an exhaust decompression valve will be high.

 

[Miami_Oh_Yeah!]

, and torque to 20 ft-lbs.

If I recall correctly, the spark plug torque on the TR-1 engine is 9.8 ft-lbs in my service manual for my VX waverunner. The NKG spark plug box says like 8.5 ft-lbs. Torquing to 20 ft-lbs may break off the spark plug in the cylinder (ask me how I know)

Edit: nevermind, I see he is considering a AR 190 and not the AR 210 with twin TR-1s

 

[JDRacing]

If I recall correctly, the spark plug torque on the TR-1 engine is 9.8 ft-lbs in my service manual for my VX waverunner. The NKG spark plug box says like 8.5 ft-lbs. Torquing to 20 ft-lbs may break off the spark plug in the cylinder (ask me how I know)

Edit: nevermind, I see he is considering a AR 190 and not the AR 210 with twin TR-1s

Yes, somebody please correct me if I'm wrong, but I believe the torque spec on the 1.8 HO for spark plugs is 18-21 ft lbs. Just torqued mine to 20 last week with no problem.

 

[David Martin]

My service manual 2013 calls for 18.4 FT LBS on my year........... I always used a little anti seize and my wrench always clicked at the 18.4 at around the 5 o'clock position and NKG calls for hand tight with a 1/2 turn from 12 to 6.

I just changed my plugs today after 2 years.............not recommending a 2 year change..... I have been busy with moves ect........the last 2 years and just hit 70 hours on my plugs and they look good on the plug read. I now can see why Yamaha 1.8 seem to need a plug change so often..........I did a compression check just for fun.............196PSI front cyl, 200psi, 189psi and192psi COMPRESSION PRESSURE was on a cold engine, reading like those will be hard on plugs for sure!!!!!! both engine are almost identical in pressure.