T9.9 high thrust starting/running problem

[tmjb]

I am new to outboards but experineced with carburetted gas engines and have a problem with a recent, low hours T9.9. It will not start or run unless I block half of the air intake (with tape etc), when it runs fine unless I lower the revs completely at when it stalls. Plugs are a little sooty. I thought it must be a choke (does it have one?)/starting device problem, but that does not make sense since then I would expect that with the restricted air flow it would stall when hot (and hence over rich) - unless the mixture is too lean to begin with. How do I adjust? Is it the brass nut/screw at the bottom of the carb?

I just aquired this engine (but it is obviously almost new and little used) and am told that previouusly it ran fine once started.

Any advice would be much appreciated.

Thanks in advance.

[jb123]

your carburetor needs a good cleaning.

[tmjb]

Thanks for the reply. Do you think that is the case even though it has been used very little?

[jb123]

assuming you have good flow/clean gas getting to the carb, yes. if it has sat for longer than a couple months the carbs will gum up.

[tmjb]

Thanks again. Does the type of cleaning you refer to require disassembly or is it possible to spray a cleaner or put an additive in the fuel?

If disassembly is required is this something to have a dealer do or could a reasonably mechanically savvy individual (me) do it (I used to maintain my cars and rebuild engines etc before the days of comuters and furle injection etc.)?

It seems to me like the jet must be clogged since it runs reasably well with half the airflow constricted. It powers the boat fine in this condition its just a little tempremental at low revs (when changing gear).

[tripleb]

Hey tmjb,

Carburetor dis-assembly, cleaning, and re-assembly, is very straight forward. If you have ever rebuilt an automotive carb then the outboard is a "piece of cake".

Good luck

[tmjb]

Do I need to buy a gasket or similar set or are the current gaskets likely to be reusable?

[tripleb]

Hello tmjb,

Typically, the gaskets can be reused. If not, one carburetor kit shouldn't be terribly expensive.

[jb123]

yea, on a motor that new, you will only have to replace what you break. tear it down as far as possible and spray a good carb cleaner thru all orifices.

[tmjb]

Many thanks all for your advice. What type of carb cleaner is recommended during the rebuild? I read somewhere that regular automotive carb cleaner and fuel additives are not recommended for outboard engines.

[tripleb]

Hello tmjb,

Regular automotive carb cleaner will work just fine.

[Pacific Offshore]

I would clean it up good, clean the fuel filter/strainer and ensure that the gas is clean or not too old, (less than one year). I would suggest that you purchase a gasket kit for the carb as it is easier to use, and ensurs that all components are re-assembled with no air leaks.

Good luck!

[tmjb]

Thanks again.

[brittanydog]

TMJB,

I have a 9.9 high thrust and have 3 friends with the same motor(all of these motors are in the 1997 vintage). We use them here in the NW to slow ***** for salmon. ALL, let me repeat ALL 4 of these 9.9 high thrust outboard are dogs to start. They are all electric start and takes 5-10 sec to get them started cold, it take anywhere from 15-20 secs where the motor just runs like it ready to die, but after it goes through this phase it speeds up and runs great. It's only does this when cold. After it warm and runs for 30-40 sec it runs great.

[tmjb]

Interesting about the slow starting. That's true for this one also, but then it has this problem that once started I have to block half the airintake for it to keep running and keep it that way even after warmed up or it stalls out.