Nissan 30hp issue..

[PLP]

Hi!I was looking for help,and there seems to be some very knowledgable people here.

I have a 1998 Nissan 30hp tiller control on a 14x48 alumicraft.

My issue is that when it is wide open,the power fades,when I back off it picks back up.I may lose 3-5mph.

Since this issue I noticed my top plug wire was slipping out of the boot.I got some electrical tape,and taped it real good.A friend tried to move the plug wires while it was running,and just touching the wire shocked him bad..It shouldn't do that should it?

I have installed a see thru filter,and I have noticed there was air getting into the line.And that the fuel would drain back into the tank.I replaced the fuel tank,and bulb.There is still a small amount of air in the fuel line.The power fade problem isn't quite as bad,and when I pump the bulb it does seem to pick back up.

I also noticed as I turn the handle the carb opens,and I assume the timing changes as well,but just before wide open the carb quits moving,but the timing keeps going.Could it be getting out of time on top end?

Do you think this is a fuel line fitting issue,or fuel pump issue?

With no one but me and my son in the boat it will fly,and doesn't have that problem.It is just noticeable when there is a boat full of people.

Thanks in advance!

 

[deejaycee_2000]

Re: Nissan 30hp issue..

Hahahaha, yes it will shock you! Best to replace the boot with NGK ones, tohatsu ones aren't great .... at first they are fine but as they get older they give problems .....

Doesn't sound like a fuel issue to me either, you need to sync the carbs and adust the timing, also just check the air/fuel mixture ......

 

[Sea Rider]

Re: Nissan 30hp issue..

If it's a 2 strokes engine, some hints and tech information:
Ignore if it's a 4 stroke

1-Cut 2-3 mm portion from plug cable end, so to have new wires portion matching new plug connectors. Tohatsu are NGK factory delivered, which are not so cheap about $ 20 each, wrap several turns of 3M electric tape in the portion where plug cable sheath ends against connector, to stop any electric leakage there as the sheath is slight less longer than it should be.

2-Carb must be perfectly clean for engine to work well. Get all air out from fuel line, push and hold engine end valve open and squeeze primer bulb to release air until good amount of gas exits.

3-Check gas pump diaphragm for leaks, change if required, check also the gasket that seals pump to engine body for deterioration. Adjust well pump screws. Set plugs gap to 1.0 mm.

4-At full throttle, 25? mark should be in straight line with mating surface, photo 1. Adjust by means of first stopper untill reached position. You can turn lower stopper full clockwise untill seats as there is a slight throttle end play that is useless to have, tiller handle will move slight to the left stopping at first line (where turtle is) if engine has slight more rpm than before, adjust CCW idle vertical screw to lower to 1K rpm. Forward gear must not make a loud clack or engine stop when gearing, readjust slight CW if necessary.

5-If entire engine is out of adjustment (check photo 2)

1-Advance timming should be 21 mm measured between both outside nuts in straight line.

2-Throttle adjustment should be 46 mm measured from black plastic end to beginning of outside nut in straight line, adjust both accordingly if out of specs. Use a small caliper to measure.

5-If your engine has had hard use & abuse, will recommend to change all entrire small white/black parts that moves/slides/links all throtthle components, are cheap, will have a factory looking & working engine. Check service manual parts to order, ask TG or Pvany for them.

Hope this works,

Happy Boating

 

[PLP]

Re: Nissan 30hp issue..

Thanks for the reply guys,and super big thanks to you for the huge effort sea rider!

Yes it is a 2 stroke..sorry for the oversight.

The spark plugs,and boots are NGK.I will have to undo them,and re-wrap them with the 3m tape.

I did some thinking,and what I did today was take out the stock filter that was in the engine compartment,since I have a filter on the lline.I also purged the line like you said sea rider.

After those 2 adjustments It did run alot better today.It still faded a hair,but picked back up,and ran stronger than before.ALL of the linkage has alot of play.I am going to check out the things you mentioned.

Also it appears there is oil on the motor,and it's trying to get into the carb,so i must have a leak somewhere.

Thank both of you so much!

 

[PLP]

Re: Nissan 30hp issue..

Sea rider I looked at my carb at WOT and it is on the right side of the hump in the dished section to the right of where your picture shows it is suposed to be on the left side of that hump...What problems could this cause?This is a new carb that some guy at a local marine place installed.

This boat is a 14x48 jonboat.It weighs 250#,I am 280#,I also have in it 2 deep cycle batteries,it has another 100# of accessories,plus the motor weight,and with a 220# friend in the front it runs 33mph down river,and 28mph upriver.Does it sound like the motor is pushing it pretty good?I have a stainless steel 3 blade prop with about a 10" diameter and the pitch is 10.

Thanks again!

 

[TOHATSU GURU]

Re: Nissan 30hp issue..

"Also it appears there is oil on the motor,and it's trying to get into the carb,so i must have a leak somewhere."

You have a two-stroke...There is no oil to leak as it is mixed with your fuel tank.

"I looked at my carb at WOT and it is on the right side of the hump in the dished section to the right of where your picture shows it is suposed to be on the left side of that hump..."

The carb is on the front of the engine and can only be at one point.

 

[PLP]

Re: Nissan 30hp issue..

"Also it appears there is oil on the motor,and it's trying to get into the carb,so i must have a leak somewhere."

You have a two-stroke...There is no oil to leak as it is mixed with your fuel tank.

"I looked at my carb at WOT and it is on the right side of the hump in the dished section to the right of where your picture shows it is suposed to be on the left side of that hump..."

The carb is on the front of the engine and can only be at one point.

Maybe I should have been clearer..

It appears as though I have a fuel leak bc an oily residue is on the motor.When I say oil I was along the lines of what the 2 stroke oil film may look like.

Also the carb comment...I was saying that the white bushing that controls the throttle on the carb in his photo is not where my white bushing is.

 

[Sea Rider]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Hola PLP

1-Have you checked if 21 mm and 46 mm are achieved to start with ?
2-Are you matching the 25? mark with mating case dont' you ?
3-If point 1 is at factory specs, probably stopper A (Upper one) is badly adjusted, free nut CW some mm away to the left, turn stopper screw CCW so that the advancer arm reaches out more to the right while throttleing to wot, will see that the carb collar has advanced to the left.

Once at full wot, carb at 180?, readjust stopper nut to that position. Is it possible to place pictures ( better than 1K words) to have a closer look. If throttle linkage is badly adjusted you will have a 25 HP performance rather than a 30 HP one.

Full wot tiller handle and take a photo of the collar/throttle cam final position. This is a fairly easy to do job, but will need visual information to understand your actual engine state.

About the tape, you must only cover the missing sheath portion adjacent to the connector with several wrapps of tape. Are you running your engine with factory delivered prop ?

PD: The gear lever must be at forward setting for the adjustment, if in neutral white roller/cam will be seen to the right, not matching pic sent which is at forward gear and full throttle.

Happy Boating

 

[PLP]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Hola PLP

1-Have you checked if 21 mm and 46 mm are achieved to start with ?

The 21mm was on,but the 46mm was not.I had alot of excess play on the low end,after the adjustment I was getting enough throttle to break the white bushing across the hump,and put it exactly as pictured.

2-Are you matching the 25? mark with mating case dont' you ?

It appears to be at the 20? mark?So will it cause my engine to just be 25hp instead of 30hp,or what else may it cause?I will post some pics..

3-If point 1 is at factory specs, probably stopper A (Upper one) is badly adjusted, free nut CW some mm away to the left, turn stopper screw CCW so that the advancer arm reaches out more to the right while throttleing to wot, will see that the carb collar has advanced to the left.

None of my stoppers reach any part of the linkage.I will adjust them.

Once at full wot, carb at 180?, readjust stopper nut to that position. Is it possible to place pictures ( better than 1K words) to have a closer look. If throttle linkage is badly adjusted you will have a 25 HP performance rather than a 30 HP one.

AT wot the stopper is about 1/8" from the linkage.I will adjust it in.

Full wot tiller handle and take a photo of the collar/throttle cam final position. This is a fairly easy to do job, but will need visual information to understand your actual engine state.

I've got that fixed now,since the 46mm adjustment.

PD: The gear lever must be at forward setting for the adjustment, if in neutral white roller/cam will be seen to the right, not matching pic sent which is at forward gear and full throttle.

LOL..that's exactly what I did wrong!I starting looking around,and figured I needed to put it in gear.After doing so,noticed it was still short of rolling over the hump,but after I did the 46mm adjustment it goes all the way open now.

Are you running your engine with factory delivered prop ?

No it is a stainless steel prop,aftermarket.

About the tape, you must only cover the missing sheath portion adjacent to the connector with several wrapps of tape.

OK,I did a little too much..lol

Thanks again for your time,knowledge,and patience!

 

[PLP]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Here are 2 pics..Looks like My timing is not set right..My picture angle is a little different than your picture..It is set at 20 degrees not 25 degrees..how do I adjust it?How big of a difference will that make?

I also just noticed I need to go re-tighten the set nut on that linkage where I made the 46mm adjustment..lol

 

[PLP]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Quick question..If I shorten the 21mm adjustment will it increase timing?

 

[Sea Rider]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

PLP,

You are right on what you are doing, looking at your pics, you're just 2-3? off from 25? timmimg mark. Forgot to mention previously that upper linkage can be adjusted from 20.5 mm to 21.0 mm, a 1/2 CW in turn will shorten space by 0.5 mm. Before adjusting, seems that ball joint 1 and ball conecctor 2 have excesive side play would advise to change them including rod snap(3) + black nylon snap(4) + cable pin(4) all 5 parts looks completely worn out. Check pics.

Parts that will need:

(1) 346-05228-1 Ball joint B (1)
(2) 3B7-05243-0 Ball joint connector C (2)
(1) 3B7-63733-0 Rod snap (3)
(1) 346-05234-0 5 Rod joint (4)
(1) 353-83728-1 Cable pin (5)
(2) 345-05223-1 Rod snap (moves advancer along with carb cam)
(3) 345-63207-0 Collar 9.8 (helps slide throttle shaft inside tiller handle)
(2) 345-63063-0 Throttle shaft supporter (supports shaft)

Lubricate with a thick oil drop (car engine oil) all these components, changing them will compensate the sligh 2-3? difference. A good adjustment will be : once carb butterfly is at 180? (wot, at extreme left of cam) the white collar must turn freely with fingers, readjust accordingly with stopper A. Apply 1-2 oil drops inside shaft and roll collar for oil to penetrate. Parts are available and cheap.

If you want to get the best engine/boat performance, perform a wot test with a tacho and see what is your max rpm at full throttle, Max wot rpm 5,150 to 5,850 rpm, the standard factory prop is a 9.6 x 13 and 9.8 x 12 for slight heavier boats. If any other issue not clear, just post, you are welcome at any time, that's the purpose of the forums, to share information and lower operational boating costs

Happy Boating

 

[PLP]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Thanks searider!I will follow up.

I do appreciate it,alot of guys just say..check your owners manual.I really appreciate you taking the time to explain in great detail...Not many people will go to that length to help others...I'm going to put her in the water tomorrow,and I will report back later..Thanks again!

 

[PLP]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Ran her today,and she ran a whole lot better.Way more power!I am getting air in the line,so I have to figure out where that's coming from.I guess it was a combination of alot little things.I need to replace the plastic parts as suggested.Thanks a ton!

 

[Sea Rider]

Re: Nissan 30hp Adjustments

Re: Nissan 30hp Adjustments

Ran her today,and she ran a whole lot better.Way more power!I am getting air in the line,so I have to figure out where that's coming from.I guess it was a combination of alot little things.I need to replace the plastic parts as suggested.Thanks a ton!

Happy to know it's working much better, if still getting air on line, get a complete new line, part 3B7-70200-3 (Primer bulb assy) let us know how it went after replacing suggested small parts, a must replace due job

Happy Boating