Starts and runs at idle great on muffs or in a bucket - won't start at all in the lake or ocean.

[raftingtigger]

We have a 2006 Mercury 9.9hp manual start motor that was just professionally serviced. Before service it was hard to start, but got much better after I cleaned the carburetor. After service it starts with 1-3 pulls - when at home and we are using muffs or if we have the lower part in a bucket. When we go somewhere it often either won't start or takes 20 - 30 pulls to start. It then seems to run fine.

We've had it out 3 times since the service. Twice we gave up starting it and just used the back up trolling motor. The other time it worked fine. This week we had it out for a boat camping trip. Motor just wouldn't start, so we used the electric troller to get to the campsite. The next day it started reasonably several times. The last day it woudn't start again and we used the troller to get back to the boat ramp. It is really frustrating.

We're reluctant to take it back to the shop: It starts and runs great at home (so probably would at the shop also), the service (with only a few small parts replaced) cost us $500, and they wouldn't even fix the carburetor fuel leak. I had to do that myself.

We've done all the basic troubleshooting: Fresh fuel, vent open, bulb works and provides gas to the engine, spark plugs clean, kill switch ON, choke either in or out, primer used per instructions, did flooded start routine (choke on, prop disengaged, throttle open).

Anybody have anything similar? Is our motor allergic to the water? Yes we are replacing it with a 20HP when they are back in stock.

 

[gm280]

Interesting... When you can't get it to start, you've verified that it does have fuel up to the cab...correct? And if so, have to verified you have spark as well? If you have both and it won't start, have to tested the compression on it? If you have good compression, good fuel and properly timed spark, there is no reason for it to not start... JMHO

 

[tpenfield]

I think the engine does not like being away from home . . .

I wonder what 'serviced' really means . . . lots of people say "I just had it serviced and now it . . . "

$500 . . . I'm in the wrong business

Like GM said . . . when it won't start, go through the basics . . . Fuel, Spark, compression.

Is there anything different that you do at home when running the engine vs. out on the water?

Maybe check the safety lanyard wiring (or kill switch wiring)

 

[raftingtigger]

Serviced means my husband took it to a reputable dealer and had them "service" it. They replaced the water pump impeller (yes, it was bad, at least the part they sent back) and replaced the primer button (again, the part that came back was bad) and tuned it up. They noticed a slight fuel leak from the carburetor and said they did not rebuild carbs. I have no idea what else they did. I did clean the carb again and now it doesn't leak.

Fuel: What is different about home vs at a body of water. No idea, no reason to be different. IF I can get it started and running for more than1 min it works great and stays running under load.

Spark: If this is the problem why only at a body of water?

Compression: Again, why only at a body of water? Also runs great IF it starts.

So what is different?

• The motor is tilted up and jostled about on the road.
• The water is colder.
• It's not at home and we want it to work.

The only other thing I have noticed is the bulb sometimes doesn't get hard. This could be the entire problem. It is a new bulb and hose. Looks to be in really good shape and the hose clamps are tight. Could it be leaking air at the quick connect to the tank? But why does it work at home and not away? I have now removed and reset that connection. Will update. Going out tomorrow.

Thanks for the thoughts. Old boater, but new to gas powered ones.

 

[wn6ngp]

When the motor is at the lake the lower unit is fully submerged which provides back pressure to the exhaust which can make a marginal motor difficult to start/run. I've experienced this numerous times. That bulb should pump up firm every time. If not then there is at least one problem somewhere in the fuel supply. If your service guys "don't do carburetors" then you need to find an old school mechanic. You have to search but there are usually some around only too happy to not have to work with check engine lights ECMs etc.

 

[racerone]

Does this motor sit with fuel in the carburetor all the time ?------Run fuel out of the carburetor at end of each adventure.-----An empty carburetor stays clean.

 

[raftingtigger]

Don't know how to empty the carburetor, but doubt it is getting dirty in the space a week or two. I'll consider that if the motor will sit idle for any length of time.

 

[Texasmark]

When the motor is at the lake the lower unit is fully submerged which provides back pressure to the exhaust which can make a marginal motor difficult to start/run. I've experienced this numerous times. That bulb should pump up firm every time. If not then there is at least one problem somewhere in the fuel supply. If your service guys "don't do carburetors" then you need to find an old school mechanic. You have to search but there are usually some around only too happy to not have to work with check engine lights ECMs etc.

Exhaust relief ports at the rear below the powerhead should have solved that problem.

Don't do carburetors is a clue to a potential problem.

Do you have the engine on a boat transom (vertical) or toss it in the trunk (horizontal)?

How frequently do you take it to water to run, not at home on the muffs of bucket? How soon after running at home do you take it to water?

Do you know for sure that the choking device really works?
Did you ever pull the plugs at the water and check for wetness indicating fuel present and/or maybe flooded...do you smell fuel when trying to start...oily slick on the water?

Have you tested for spark at the water?

 

[gpfishingdude]

Spark-fuel-compression. My 50 hp. did the same thing this spring so I checked the compression on each cylinder and took the carburetors into a shop and had them cleaned and rebuilt. While waiting on the carbs to be rebuilt I checked the spark and found that I had spark to half of the cylinders. I changed a bunch of electrical parts and then found out that I had somehow lost ground to two coils. After jumping a ground wire to the two that didn't have spark I got it running like a top.
Now that it is running and I have the special tools and testers that I bought for the job and some spare electrical parts in case I ever need them.
Total for tools parts and getting the carbs rebuilt was $650 but I have $400 worth of parts and tools on hand to work on it the next time.

 

[demarko210]

Is there anything different that you do at home when running the engine vs. out on the water?

He probably has better leverage standing and pulling at home on flat ground than he does setting/standing in the boat and pulling rocking side to side.

 

[raftingtigger]

Exhaust relief ports at the rear below the powerhead should have solved that problem.

Don't do carburetors is a clue to a potential problem.

I agree and do not plan on returning there.

Do you have the engine on a boat transom (vertical) or toss it in the trunk (horizontal)?

Always on the transom. It does get raised to the travel position for trailering.

How frequently do you take it to water to run, not at home on the muffs of bucket? How soon after running at home do you take it to water?

Less than 24 hours, closer to 10 hours.

Do you know for sure that the choking device really works?
Did you ever pull the plugs at the water and check for wetness indicating fuel present and/or maybe flooded...do you smell fuel when trying to start...oily slick on the water?

Have you tested for spark at the water?

Choke definitely works. Pulled the plugs at home. Yes, occasionally smell fuel and see a thin slick. If that happens I go to flooded start method.

 

[raftingtigger]

Spark-fuel-compression. My 50 hp. did the same thing this spring so I checked the compression on each cylinder and took the carburetors into a shop and had them cleaned and rebuilt. While waiting on the carbs to be rebuilt I checked the spark and found that I had spark to half of the cylinders. I changed a bunch of electrical parts and then found out that I had somehow lost ground to two coils. After jumping a ground wire to the two that didn't have spark I got it running like a top.
Now that it is running and I have the special tools and testers that I bought for the job and some spare electrical parts in case I ever need them.
Total for tools parts and getting the carbs rebuilt was $650 but I have $400 worth of parts and tools on hand to work on it the next time.

Thanks, this is unlikely to be our problem. Ours is a 2 cylinder and I like to think I could tell if it isn't firing on one. Also if the shop didn't check that we REALLY got ripped off. Nor does it explain working well at home.

 

[raftingtigger]

He probably has better leverage standing and pulling at home on flat ground than he does setting/standing in the boat and pulling rocking side to side.

SHE does have slightly better leverage at home, most of the time. Sometimes I'm pulling from outside the boat at home and probably don't have a better pull. This could easily be a contributing cause.

 

[raftingtigger]

Update: Took the boat to the ocean 2 days ago. Started 4 times with 3 pulls each. Died after 30 seconds the first time. Didn't want to restart until I used the a flooded technique that time, but fired right up then. I think the motor knew I meant business - as I had put all FOUR of my trolling batteries in the boat just in case.

The boat is underpowered when loaded with 2 people and diving gear OR at altitude with 2 people. We have put a deposit down on a Tohatsu 20hp electric/manual start. We would still like to find out the issue, so we can eventually sell the 9.9 Merc ethically.

 

[Texasmark]

I agree and do not plan on returning there.


Always on the transom. It does get raised to the travel position for trailering.


Less than 24 hours, closer to 10 hours.

Choke definitely works. Pulled the plugs at home. Yes, occasionally smell fuel and see a thin slick. If that happens I go to flooded start method.

That eliminates all that. Do you find fuel around the inside of the cowling traceable back to the carb venturis? Would occur when the engine was tilted up...source improper float level or needle valve that the float controls isn't sealing properly.

Update: Took the boat to the ocean 2 days ago. Started 4 times with 3 pulls each. Died after 30 seconds the first time. Didn't want to restart until I used the a flooded technique that time, but fired right up then. I think the motor knew I meant business - as I had put all FOUR of my trolling batteries in the boat just in case.

The boat is underpowered when loaded with 2 people and diving gear OR at altitude with 2 people. We have put a deposit down on a Tohatsu 20hp electric/manual start. We would still like to find out the issue, so we can eventually sell the 9.9 Merc ethically.

Under powered means deposits in the cylinders and exhaust passages from incomplete combustion. HP is (Torque x RPM)/5252, common units. 2 strokers are usually short on cubes and thus stroke meaning torque is weak. Gotta get the HP out of RPM. If you are overloaded and engine can't run up in the top of the recommended band, you don't have RPMs...so you don't have HP. Shallow pitched props are usually the answer to under power situations which allows the engine to run properly even though the boat isn't/may not be propelled all that well.

Tohatsu makes some Merc. engines in the lower HP area. Every T owner I met loves their engine. Good choice and at 2:1 you should enjoy your boat with adequate power.