Nissan 140 inline fuel filter

[Boattoo]

I have a 2002 Nissan 140 HP. Runs great on the portable gas tank. Will run to 5500 rpm. Knowing the boat had an old built in gas tank and being concerned about sediment etc. I put a plastic inline fuel filter in front of the water seperator filter that is inline also. The boat ran good on the main tank until approximately 6 hours of running and now it seems that the plastic inline filter needs replaced as it has trapped sediment. The boat began taking additonal time to accelerate and would only run up to 5000 rpm. My questions are: Is having the small 3/8 inline fuel filter creating a problem for the fuel pump on the engine. Is it necessary to have this filter inline or should I just use the canister filter? I am looking for best advice. I don't mind changing out the small filter or cleaning the canister more frequently as replacing the main tank is not possible at this time. Thanks for ideas.

 

[pvanv]

A good water separator should have a 10 micron filter and plenty of settling bowl, so it should be the primary (first) filter, and ideally it should be located between the primer bulb and the motor. The little inline filter you added likely clogs too easily. If you can, clean the tank, and get rid of the extra sediment that is clogging the filters.

 

[pvanv]

A good water separator should have a 10 micron filter and plenty of settling bowl, so it should be the primary (first) filter, and ideally it should be located between the primer bulb and the motor. The little inline filter you added likely clogs too easily. If you can, clean the tank, and get rid of the extra sediment that is clogging the filters.

 

[Boattoo]

Thanks Paul. I agree that cleaning the tank is the best option.

 

[Boattoo]

The engine is a 2002 Nissan 140. Last time out, 2 weeks ago, it slowed and quit running but cranked and ran back, 11 miles to the marina although it would not reach max rpm (water was rough too so I didn't try to run fast very long) I took the boat out today using the portable tank to take the built in tank out of the question. It cranked and ran good for short time although it would only get to 5300 rpm then it shut down. What are some things to look for in trouble shooting this issue. The engine would crank back up and idle slow and I was able to make it back to the marina. I could touch the head and it did not seem too hot and I did not get an alarm. The engine had been run without a thermostat (when I bought it) and I istalled a new one prior to the last outing.( a similar issue occured then) This time out the motor would get to upper rpms then quit running. What do you think gas or electrical issue? Thanks for your ideas.

 

[pvanv]

I assume your model is NF140A2 (year is irrelevant).

At this point, it could be almost anything. The most common problems are fuel and electrical.

Since you confirmed that you were getting junk from the onboard tank, you really must run a good water separator with settling bowl to keep that stuff out of the carbs. A minor air leak or weak fuel pump may cause speed limiting, but since that amounts to "running out of gas" at the carbs, you likely would not restart easily without priming the fuel. If for some reason, there is some junk in the carbs, it could slosh around, causing weird, intermittent stalling,

If you have a flaky kill switch (or associated wiring), that could cause intermittent stopping. Likewise, if you have a thermally-intermittent ignition component (which can drive a tech nuts isolating it), that could cause these types of problems. I would pull a plug or 2 immediately after the motor stalls, and see whether it is wet (probably loss of ignition) or dry (likely insufficient fuel) as a start.

 

[Boattoo]

It is the 140A2 model. I will follow up on your ideas. Could weak battery(ies) be a possible factor or should the running motor charge these quick enough to take that out of the equation? Thanks.

 

[pvanv]

TLDI motors are sensitive to low batteries, but the old 120/140 should work well even with a weak battery, since it is magneto ignition. The alternator produces about 11 amps, so it should recharge pretty fast.

 

[Boattoo]

Thanks. I will update as progress is made.

 

[Boattoo]

No Title

I was able to get to the boat today as I wanted to check a couple of things that might be causing my issue. I took off the engine mounted fuel filter and the bowl was clean. That was good as it tells me the portable fuel tank is probably not a source of crud that might have clogged carbs. I noticed that the o ring was very flat and I am going to replace it. Perhaps it was sucking air here. While there I reinstalled the thermostat and checked the sparkplugs which mostly looked black. When I got the engine I did not notice but the overheat wire had been disconected and I would like to know which bolt or screw head I should connect it too. I have attached a picture which shows the connections and two possible connection spots. The large silver bolt or the screws in the circular cover in the picture. Ideas on where to connect it will be great. Tomorrow I am thinking I will remove the airbox and oil tank and drain the carberators. That may provide some insight to the gas issue and debris I might have sucked into them.

 

[Boattoo]

Today I pulled the drain screw on the four carbs. There was debris in the gas that came out but the screws were clean and not black or gunked up. The gas looked weak however. I also put in new plugs. I have to order a new air silencer gasket to put it back together and then I will see if it runs differently. Also when I looked at the parts manual at the engine mounted fuel filter I noticed it calls for 2 o-rings in the engine mounted fuel filter. I could only locate one on the filter cup. The diagram shows one on the filter top. I will order both and replace prior to running. Hope to see a difference. Does anyone know where to ground the heat sensor. (see previous post). Any advice?

 

[pvanv]

Your photo appears to be of the water pressure switch. That takes the red/white wire. The overheat sensor is located near the thermostat housing on the cylinder head.

If there was crud in the bowls, keep the drain plugs out and prime away to flush some more crud out. That may help.

 

[Boattoo]

Thanks. I will flush as suggested prior to putting it back together and trying a run. Would the disconnected wire which is a black wire (hard to see in the picture) hook to the bright nut in the picture. I assume it is a ground. I will check on the switch near the thermostat to see where the wires go and if the black wire in question comes from there. Thanks again.

 

[pvanv]

Solid black is always ground on any Tohatsu. It should be attached to a good frame ground.

 

[Boattoo]

Thanks. I will attach it prior to running next time.

 

[Boattoo]

I will be at the boat next week and plan to use primer bulb to flush carbs before putting back together. I just put in new spark plugs. Should I take the plugs out prior to flushing carbs to prevent soaking them with gas or is this not a problem? I plan to connect the black wire referenced in the earlier picture to the silver nut in the picture. Hope its the right spot. I have looked in the manual but donot see this wire and connection. Thanks for reply and ideas.

 

[pvanv]

Fuel should only get delivered to the intake if the motor is cycling, so no problem. Connecting the wire should be OK. I hope you don't end up having to pull and clean the carbs, as that is a time-burner.

 

[Boattoo]

Thanks for the advice. Sometimes we do things we know perhaps we shouldn't. In this case, running on the old inboard tank, the engine ran fine prior to that experiment. I'll just have to clean it up and go from there. Thanks again for the advice.

 

[Boattoo]

Well, I got everything put back together put the boat in the water and would not crank. No spark/fie. Not sure what might have happened as really didn/t do anything electrical other than change plugs. Prior to this the boat cranked on the first turn of the key. At a loss but will be having a tech come and look at it as the problem is one I may not resolve alone. Is there a main fuse or similar on this motor that may have tripped or blown? Other ideas or things to check?

 

[Boattoo]

I had a tech look at the boat today. News not good, no compression in one cylinder. Most likely will be the end of this motor. Compression in other 3 was near 150. He felt lean fuel caused problem. Without pulling head won't know extent of the damage but the estimate puts it out of my reach or need to repair. Will most likely sell parts as all electrical, trim, lower, etc good and functional. Someone who can do the work might be interested in the motor as th tech said you may get by with boring one cylinder and replacing piston. Again, would have to pull head to see. Just thinking out loud. Any ideas or advice.