I hate 4 Strokes

[bullie]

I think its gonna make me have a stroke before I get it to run.

I have been trying to get a Nissan 9.8 NSF9.8A3 working for a guy. I have spent way more time on it than I care to admit. The story is that it never ran correctly even when new. The dealer had someone come out several times to work on it, each time saying it had a carb problem, but nothing was ever resolved. As it was told to me the previous owner asked for a new motor, the dealer said no, and the motor went in to storage until the current owner bought it and put it on his boat.

I did not have a fuel pump when I first looked at it. I installed a new one and cleaned the carb and eventually got it running. It ran for a couple weeks and then quit. I cleaned the carb over and over thinking it was a fuel issue. I gave up and put on a new carb this morning. Still the same thing. It will not start unless the throttle is advanced and then will only run if the choke is engaged. It will die if I attempt to throttle down or if I disengage the choke.

I don’t know if it has an issue that is not related to fuel or if there is an air leak somewhere. I don’t have any idea why it won’t run. And, this morning after dropping the plastic spacer that goes between the intake and carb in the lake and the resulting swim I found that I wasn’t in the mood to work on the motor any more for awhile. The water was surprisingly cold but luckily only about chest deep.

[PugetSoundBoater]

A plastic spacer between the carb and intake? Look there for a crack or a warped surface.Gasoline and heat could do some damage to the spacer. Check the mounting surfaces and use gasket sealant?

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[amuller]

I don’t know anything about this engine. Does it have a cam drive belt that could be out of time? How is the compression? Valve clearances? Ignition timing? (Sheared flywheel key?) Can you tell from the plug whether it’s running rich or lean? Most likely something fundamental is wrong here.

[bullie]

Gonna go back and check timing this evening. I feel like I know less than when I started.

[jerry-ahrens]

Most 4 stroke outboard carbs that I’ve worked can be difficult to get clean. I had a Honda 25 once, that I ended up replacing one of the carbs to finally get it to run. I like to use Power Tune spray ran thru all the passages, then let soak. Follow that with a rinse of B12 Chemtool carb cleaner. The last step is to blow it out with compressed air. You would think that a brand new carb would eliminate the other one being dirty or plugged though…
I’ve rebuilt some of these in the past, only to have the owner store them with ethanol gas in the caburetor…. then come back and complain why they won’t run properly.

[kees]

.
when my four stroke Suzuki runs awful , its always a dirty carb. 🙁
clean the nozzle ( also that part what sticks in the intake manifold ) and ……..off you go again
at least, that’s what my dealer tells me when I asked him what the problem was.

Had the same problem with my Honda two weeks ago,
thought, maybe I can fix it myself.
After cleaning the carb. and the NOZZLE !
it runs nice again. 😎
😎
.

[fleetwin]

quote amuller:

I don’t know anything about this engine. Does it have a cam drive belt that could be out of time? How is the compression? Valve clearances? Ignition timing? (Sheared flywheel key?) Can you tell from the plug whether it’s running rich or lean? Most likely something fundamental is wrong here.

Good advice, I forgot all about this basic four stroke stuff!

[fleetwin]

Correct me if I am wrong, but you said you replaced the carb and fuel pump with new…Are you sure the fuel flow to the carb is OK? Did you pull the bowl drain plug (if equipped) and pump the primer bulb? Perhaps there is an air leak somewhere before the fuel pump. Can you keep the engine running if you pump the primer bulb continually? How did it run/idle when you had it running for a few weeks after replacing the fuel pump?
Seems like this thing does have some original defect that was never resolved. I guess the carb and fuel pump are not to blame. Don’t know what the intake manifold looks like, perhaps there is some sort of air leak there….
Hopefully someone with more Nissan experience will respond….
For what it’s worth, I hate em too….

[pm-t2]

I fail to understand why the Moderators allow the discussion of Nissan outboards on this site.

Bestd,
PM T2

[billw]

quote PM T2:

I fail to understand why the Moderators allow the discussion of Nissan outboards on this site.

Bestd,
PM T2

I don’t know why they allow Nissan outboards in the COUNTRY; but that’s just me. Maybe this one is not quite an antique yet but someday it might be, if it’s taken care of properly now.

I agree with the other guys…The carbs on these things are tough to get clean…The low speed circuit will have the tiniest imaginable jets…However….If it never ran right to begin with, maybe a Nissan (or Tohatsu, same darn thing) dealer can find a service bulletin on it. Tell me what year it is and maybe I can find a corresponding Mercury service bulletin, because, gulp, Tohatsu makes little Mercurys too. Carl’s head would absolutely blow right off his shoulders, if he could see this day.

Long live American manufacturing!

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