Nissan 3.5 runs rough above half throttle and slow to warm up

[jeffinatl]

Hi Guys,
My newish Nissan 3.5 is making me want to pull my hair out.
We bought this motor new about a year ago. It didn't run smooth on our 1st trip to Florida. It would crank, but would cut off a lot while motoring. We brought it back to the marine store and while they had it they called Nissan and Nissan suggested that they increase the idle speed. We picked the motor back up.
I run my motors in a trash can with water in it every weekend that I do not go boating. After a couple of weeks, the motor would not crank. We took it back to the marine store and they did some adjusting and we picked it back up. After a few weeks, it would not crank again.
We took it back to the marine store and they got Nissan to agree to replace the carberator. We took it home and the next week it would not crank again. Let me point out that I use fresh gas with ethanol formula stabil in it so that is not the problem.
We took it back to the marine store and told them that this motor must be a lemon and would they please ask Nissan to give us a new motor. Nissan agreed to ship the motor back to them. They kept it a week and shipped it back saying that they had done some work on one of the cylinders or something and we figured that we would be good to go.
It does crank everytime now, but it is slow to warm up. It takes about a couple of minutes with the choke out and even then it might die if I give it some throttle and I have to crank it again and rev, rev, rev in short bursts to get it going without cutting off.
A bigger problem than that is that it will only run smooth up to half throttle. This is the part that is the most dissapointing. Anything more than half throttle makes the motor run rougher and slower the more throttle you give it.
This is the same in gear or in neutral. It makes no difference.
Anyone have any ideas what might be the cause or the solution to this.
thanks,
Jeff

 

[Sea Rider]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

If in warranty, ask for a new engine. Personally wouldn't want an engine with so much tech issues after having being hackneyed by dealer 3 times with no avail.

Not Happy Boating

 

[pvanv]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

Could be a lot of things, but likely fuel related. Have the dealer get it squared away for you under warranty.

 

[jeffinatl]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

If in warranty, ask for a new engine. Personally wouldn't want an engine with so much tech issues after having being serviced more than 3 times with no avail.

Not Happy Boating

I hear you about not wanting the engine, but I did ask several times that Nissan replace the engine, but they refuse to.
As mentioned in my earlier post, Nissan did finally agree to ship it back for inspection. The made some adjustment and sent it back. I don't think that I will ever buy Nissan again.

 

[jeffinatl]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

Could be a lot of things, but likely fuel related. Have the dealer get it squared away for you under warranty.

I agree, but not likely fuel related as I use the same fuel from the same can for my Yamaha 8 which never has any problems, starts fast and runs like a top.
I use ethanol formula stabil in my fuel and change out my supply can every 2 weeks.
Even a new carberator did not solve the problem as this was one of the things that Nissan agreed to do.
Jeff

 

[pvanv]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

I agree, but not likely fuel related as I use the same fuel from the same can for my Yamaha 8 which never has any problems, starts fast and runs like a top.
I use ethanol formula stabil in my fuel and change out my supply can every 2 weeks.
Even a new carberator did not solve the problem as this was one of the things that Nissan agreed to do.
Jeff

Jeff,

Not necessarily the fuel supply per se, but rather the fuel system. That is 70-80% of the problem(s) with any of the modern epa-rated outboards of any brand. FWIW, stabilizer merely slows the fuel from rotting, and is certainly nice, but not necessary if the fuel is under 30 days old.

If you need choke for an extended period of time, it is likely that the motor is too lean; adding choke masks the problem, by richening the mixture. Again, probably fuel system related.

I hope you're not serious about revving past 1/2 throttle in neutral. NEVER run anywhere above high idle in neutral, or you risk serious damage to any motor.

If you are getting misfiring at higher speeds, with no indications of fuel problems, it is possible that the rpm limiter is engaging, causing staggered ignition. That should not happen at normal operating speeds, so there is a remote possibility that the cd needs to be tested.

Your dealer should diagnose the problem, and repair it as needed. That's why you have the 3-year warranty. There is no such thing as a "lemon" motor, unless you happened to get several different problems all grouped together under one cowling, which would be extremely unusual.

Reviewing your original problem, when you say that it "would not crank", do you mean that the recoil was jammed? Or do you really mean to say that it didn't start? Two completely different symptoms, and two completely different problems. It sounds to me as though the original issue was that your motor was stalling... then later on, after some service, would not start. Is that correct?

What work did Tohatsu America do on the motor when it was back in Dallas? You said earlier that they had "done some work on one of the cylinders or something", which makes no sense to me as a technician, since it is a 1-cylinder motor, and there is nothing that could possibly be done "to a cylinder" as such. Any idea what work was actually done?

If your local dealer is unable to help you, I would recommend you call Nissan Marine (Tohatsu America) at 214-420-6440 and ask for service. Have your correct model and serial handy so they can help you. They are very helpful to consumers as well as dealers, and I am sure they will want to make you a satisfied customer.

 

[jeffinatl]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

Thank you for all of your comments. They are helpful and you seem to know quite a lot about motors. I have commented to each of your questions below.

Jeff,

Not necessarily the fuel supply per se, but rather the fuel system. That is 70-80% of the problem(s) with any of the modern epa-rated outboards of any brand. FWIW, stabilizer merely slows the fuel from rotting, and is certainly nice, but not necessary if the fuel is under 30 days old.

Jeff comment: I've been use the stabil ethanol formula hopefully to help with what I understand is damaging effect to outboards due to ethanol in gas.If you need choke for an extended period of time, it is likely that the motor is too lean; adding choke masks the problem, by richening the mixture. Again, probably fuel system related.

Jeff comment: I have to have the choke about 1/3 engaged for at least a minute and even then, the motor will sometimes die if I push the choke in after a minute without first trying to get the motor to rev a little higher. Sometimes have to rev in short bursts (rev, rev, rev) to keep motor running. After that, it will run at idle speeds.

I hope you're not serious about revving past 1/2 throttle in neutral. NEVER run anywhere above high idle in neutral, or you risk serious damage to any motor.

Thanks for the advice. No one has ever told me that. I run my motor in neutral in a tub each weekend that I do not go boating. I run it in neutral so that I can avoid slinging water out of the tub. What damage does this cause to run half throttle in neutral? Would you suggest that I run it in the tub at idle speed in neutral, idle speed in gear, a little more than idle in gear or in neutral? Don't like to have it sit if I don't go boating for a while.
If you are getting misfiring at higher speeds, with no indications of fuel problems, it is possible that the rpm limiter is engaging, causing staggered ignition. That should not happen at normal operating speeds, so there is a remote possibility that the cd needs to be tested.

Jeffs comment: The best that I can describe this is that while I am boating, I get an increase in power as I change the throttle position from start to about half throttle. Anything above half throttle does not produce an additional boat speed and the motor seems to sound not as smooth and I feel more vibration.


Your dealer should diagnose the problem, and repair it as needed. That's why you have the 3-year warranty. There is no such thing as a "lemon" motor, unless you happened to get several different problems all grouped together under one cowling, which would be extremely unusual.

I don't know what to do about my dealer anymore. They agree that the motor does not perform as a new motor should and never did, but they do not seem capable of making it run better. I have brought it to them many times. One time they told me to come get it because they had it running good and I took it home to find that I could not get it to crank.
As I said, I sent it to Nissan and they sent it back saying that they had made some minor adjustment. I do not know what else to do unless I can find a more capable small motor mechanic in the Atlanta, Ga area.


Reviewing your original problem, when you say that it "would not crank", do you mean that the recoil was jammed? Or do you really mean to say that it didn't start? Two completely different symptoms, and two completely different problems. It sounds to me as though the original issue was that your motor was stalling... then later on, after some service, would not start. Is that correct?

Jeff's comment: Yes that is correct. There have been many occasions where it would not start. On some occasions, it would start in the start throttle position, but any attempt to make it run any higher than idle, no matter how long I allowed it to idle in the start position, would cause the motor to die. Each time I would take it back to my dealer for servicing. Only one time after serviceing would it not start at all as mentioned in previous comment.


What work did Tohatsu America do on the motor when it was back in Dallas? You said earlier that they had "done some work on one of the cylinders or something", which makes no sense to me as a technician, since it is a 1-cylinder motor, and there is nothing that could possibly be done "to a cylinder" as such. Any idea what work was actually done?

Jeff's comment: Actually the dealer was vague about what was done at Nissan. I can't remember exactly what they told me, but it seemed to have something to do with the cylinder.

If your local dealer is unable to help you, I would recommend you call Nissan Marine (Tohatsu America) at 214-420-6440 and ask for service. Have your correct model and serial handy so they can help you. They are very helpful to consumers as well as dealers, and I am sure they will want to make you a satisfied customer.

I have talked with them before. The advise that they gave me was to never run the motor out of gas. They said that when you run the motor out of gas after boating, the residual gasoline in the carberator dries out and forms crystalization that is dislodged later when you add fresh gas. They claim that this leads to carberator problems that will need a carberator clean out. I tried this for a while, but went back to running it out of gas after each use because that is what I have always done with my Yamaha 8 hp and it has always run like a champ.
Nissan did not have any other solutions for me other than to suggest if it was not running right, I should take it to my dealer.

Jeff

 

[pvanv]

Re: Nissan 3.5 runs rough above half throttle and slow to warm up

Jeff,

E-10 fuel does present challenges for any carbureted motor, and especially for units that have atmospheric tank vents. The typical problems are due to ethanol's affinity for water, and its solvent characteristics. Any modern Tohatsu motor should be able to accept fresh E-10 without a major problem. Since your fuel is never more than a couple of weeks old, the fuel supply should hopefully not be a problem.

Your 3.5 may have the EPA "ratcheting" fuel cap. If so, you have a "semi-sealed" fuel system, which includes a vacuum-operated fuel pump. If so, remember that on an initial fill (with a "dry" fuel system), it will take a couple of extra minutes for fuel to flow through the filter and pump, and fill the carb, so that the motor can start. If you have the conventional cap (with the vent screw), the carb should fill (from dry) in a minute or so. Either way, when depending on gravity alone to prime the fuel system, the tank needs to have plenty of fuel, and the motor needs to be vertical, so the fuel can flow. That may be part of the starting problem.

It's not unusual for a cold motor to want some choke for a minute or 2, depending on how cold it is. Our frostbite sailing chase boats have to run for over 5 minutes before applying throttle on cold days in November and December. During that warm-up period, "fast" idle (with the throttle mark set to "restart" is usually best. The "start" mark is at dead slow idle; starting is often much easier at "restart", which cracks the throttle plate open a hair, either cold or hot (especially hot!).

If you rev way up without a load on any motor, the bearings (especially connecting rod bearings) can slap around loosely; that adds a lot of unnecessary wear; much better to be in gear anytime you will exceed say 2,000 RPM.

If you gat to about 1/2 throttle and then no more speed, just more noise and vibration, something is awry. Since the 3.5 uses a pin-drive prop, there's no possibility of a spun rubber prop hub; However, it would be good to get a shop tach on the motor to see what RPM you are getting when this happens. If the motor is exceeding the designed max RPM, the ESG (speed governor) will engage, causing staggered ignition. That definitely can happen in neutral, and may well happen if the prop is under-pitched (but that's not likely). Putting all the clues together, I am still suspecting insufficient fuel delivery.

If your delaer is pulling his hair out, see if another dealer can help you. Sometimes, a "fresh pair of eyes" can uncover a problem. See http://www.tohatsu.com/dealersearch...te=GA&Category=Both&RADIUS=100&submit2=Search for the dealer finder. It seems that there are about 5 dealers within about 40 miles of Atlanta.

I dunno about someone saying to "never" run the carb dry. Today's US gas is so crummy, that a week or 2 of sitting in the carb can cause varnishing in the small carb passages. We always run all our carbs out. Any residue in the bottom of the bowl should hopefully not be a problem, but if you want to be super-sure, you can open the carb bowl drain after running it out. That will drain the last 1/2 teaspoon or so of remaining fuel. Then the carb is really empty, and there isn't any fuel to go bad. Of course, a completely empty carb will take a couple of minutes to refill when you're getting ready to start the next time.

My money is still on a fuel system "gremlin", but based on your high-speed symptoms, there may be something else going on. Your technician will need his (or her) "sherlock holmes hat" to really diagnose the problem. Again, if you can't find a holmes (or at least watson) in your area, give Nissan Marine a call, and they can probably get you setup with another dealer.