nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

[sops786]

I have a 2005 nissan 9.8hp 4-stroke. It was running fine up until two weeks ago. On my way in from cruising the river, I hit what felt like a tree stump. It may have been floating slightly beneath the surface because that area of the river is at least 20 feet deep. Nevertheless, I cruised in quite nicely with no issues. The next week, the boat would not start. It starts briefly with the choke out then dies. I then was able to start without choke with the throttle more than halfway. It dies immediately when attempting to release the throttle. I checked the propeller and it turns freely. Also what was concerning was the water stream from the pee hole was extremely hot immediately after starting. It has a good solid stream of water but crazy hot to the touch and only after a few seconds with the engine running. I changed the impeller, spark plugs and fuel filter. Still the same problem. Can anyone please tell me what could be wrong/broken. Greatly appreciate any help.

 

[pvanv]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Could be several problems... or a few ganging up on you at the same time. The starting issue is probably fuel crud in the low-speed circuit of the carb (that got jarred around during the impact). If so, a proper carb cleaning is called for.

Odd to get HOT water from the pee tube immediately, even if the stat was stuck shut. Is there any restriction in the water inlets at the side of the LU? Have you removed and tested the thermostat?

Is the oil level correct?

BTW, always change the complete wp kit... not just the impeller.

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Appreciate the response.

Hope to test the Thermostat this weekend. Will also plan to clean the carbs. I ordered a carb kit which should be here next week some time.

The oil level was very high. Way way way more than the recommended levels. I had the oil changed about 7 months ago by an authorized nissan marine dealer and expected all to be good. Can't see how this could cause this problem.

 

[TOHATSU GURU]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Oil isn't going to compress...Too much = No power. Pull the impeller back out and put in a new liner and wear plate.

 

[THudson]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

I have a 2005 nissan 9.8hp 4-stroke. It was running fine up until two weeks ago. On my way in from cruising the river, I hit what felt like a tree stump. It may have been floating slightly beneath the surface because that area of the river is at least 20 feet deep. Nevertheless, I cruised in quite nicely with no issues. The next week, the boat would not start. It starts briefly with the choke out then dies. I then was able to start without choke with the throttle more than halfway. It dies immediately when attempting to release the throttle. I checked the propeller and it turns freely. Also what was concerning was the water stream from the pee hole was extremely hot immediately after starting. It has a good solid stream of water but crazy hot to the touch and only after a few seconds with the engine running. I changed the impeller, spark plugs and fuel filter. Still the same problem. Can anyone please tell me what could be wrong/broken. Greatly appreciate any help.

Same thing happened to me on 2005 tohatsu 15hp. Hit a shallow bar, engine died and would not re-start. Was running like a top before then. Carb rebuild by dealer fixed.

 

[pvanv]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Appreciate the response.

Hope to test the Thermostat this weekend. Will also plan to clean the carbs. I ordered a carb kit which should be here next week some time.

The oil level was very high. Way way way more than the recommended levels. I had the oil changed about 7 months ago by an authorized nissan marine dealer and expected all to be good. Can't see how this could cause this problem.

Get that oil level right, and you may have solved everything, aside from the pee stream heat. As Elvin said, oil doesn't compress well. You must stay about 1/2 to 3/4 on the dipstick. Run 10w-30 FC-W oil (not automotive oil).

If that doesn't correct the running, do a PROPER carb cleaning... total disassembly (including all jets and the emulsion tube nozzle), followed by a 4-hour soak in real carb dip (from the auto parts house) of all non-rubber parts, and then a liberal blow-out with generic carb spray... then a careful reassembly, paying close attention to float height.

To test the stat, put it in a pan of water, monitor the water temp with a thermometer, and gently warm it. By 150F or so, it should be open.

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Thanks for all the great suggestions. It seems as though the carbs are the first thing to take care of. I'll clean it out this weekend and wait for my carb kit to arrive early next week.

I wanted to throw this out to you guys. With the water stream extremely hot to the touch after a few seconds, could there be an underlying problem . . . . .like a blown head gasket or something a little more serious.

I should know in the next few days after I replace the carb, but just wanted to put it out there.

 

[pvanv]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Possibly... But... If you were getting exhaust in the water jacket, you would likely see the gases in the pee stream.

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

I changed the complete WP kit and cleaned the carbs (soaked in carb cleaner overnight, then sprayed with carb cleaner in all holes and installed kit). Before I attempt to start the engine, should I not be checking the gas tank (5 gal) and fuel hose. This is the source of fuel feed and would hate for contaminated gas running through the carbs. I never did clean it out since purchasing in 2005, and I'm sure there is a lot of old gas mixed in and also hope not contaminated with water. If it needs to be cleaned or flushed, is there a way to go about doing something like this on the gas tank and hose, or should I not worry about this.

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

I changed the complete WP kit and cleaned the carbs (soaked in carb cleaner overnight, then sprayed with carb cleaner in all holes and installed kit). Before I attempt to start the engine, should I not be checking the gas tank (5 gal) and fuel hose. This is the source of fuel feed and would hate for contaminated gas running through the carbs. I never did clean it out since purchasing in 2005, and I'm sure there is a lot of old gas mixed in and also hope not contaminated with water. If it needs to be cleaned or flushed, is there a way to go about doing something like this on the gas tank and hose, or should I not worry about this.

Also forgot to mention. I tested the thermostat. When I removed it, it was not stuck open or anything like that. I cleaned it out and tested it in boiling water. It opened at around 160'F

 

[pvanv]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Yes, of course you must check and/or clean the (either 3 or 6 gal) tank. If the fuek is old, just dump it and get fresh. While empty, inspect closely with a high-powered flashlight or bright daylight.

I hope the carb soak was preceeded by a complete disassembly... and that when reassembling, you verified the float height.

I seriously hope you did not "boil" the stat at over 210F. That could damage it. If it began to open about 150 and was 1/4" open at 160F, it was working right.

Did you change the oil with the correct type, and get it at the proper level (1/2 to 3/4 on the dipstick)?

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Cheers Captain, you've been a great help. Here's all that I did

- Carb was disassembled and then soaked in carb cleaner (from Advance Auto) overnight. One thing I noticed is that it seemed to have dis-colored the inside of the carb bowl. The rest of the carb looks good. Anyway, it looked/felt clean. I did not know how to verify the float as it assembles one way and everything kinda falls into place. There is nothing that one can do to adjust. Then again, I could easily have missed it.
- The maximum heat the water boiled to was about 180'F. From what you explained, the thermostat appears to be functioning correctly.
- I changed the oil with yamaha YAMALUBE (FCW SAE 10w30) and the level is on 3/4 on the dipstick.
- Plan to dump the gas and rinse with some carb cleaner.

Will attempt to start this weekend.

 

[pvanv]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Sounds OK...

You may have spent too much time in the carb dip... 4 hours at room temp is the usual... if the anodizing was burned off the bowl, it will now be bare aluminum, which will work OK, but will be succeptible to accelerated future corrosion from water -- either dissolved in E-10, or just water contamination. If that should happen, you can just replace the bowl, without buying a whole carb. But it's OK for now.

To verify float height, you hold the carb casting inverted, and confirm that the float is parallel with the casting. Yes, the float is non-adjustable (in theory), and is supposed to be perfect, but I have seen one or two that were not. If a new Factory part is defective, you can have it replaced under parts warranty.

You can flush out the tank and hose with fresh gas. Carb cleaner may be problematic to get out after cleaning it, and may be hard on the rubber hose.

Please report back after your test run.

 

[sops786]

Re: nissan 9.8hp motor cuts off after starting. Water stream extremely HOT

Was out of town the past few days and finally got to take it out today.

I first ran a quick test at home and could not believe it started the first time. I let it run for about 5 minutes. The pee stream was NOT hot to the touch. I still cannot figure the reason why it was extremely hot before. Anyway, cool to the touch. Very pleased. I then took it down to the river (James River, Richmond, VA). It started first time again and now I find it very responsive. I believe this may be due to oil level being correct now. It was way above the max mark before. The only thing I've found is that the motor seems to rev a little higher than before. Nothing too extreme. Just an observation.

Thanks again Captain for the great advice and suggestions.