Can too much oil cause starting problem?

[Joe Kay]

I purchased my new 2016 Tohatsu 5 hp 4 stroke on line and took it to an authorized Tohatsu dealer for the pre-delivery check since this was not done by the vendor.
When I got it back I found that the crankcase was over-filled by 8 ounces. 23 ounces of oil in a crankcase with a 15.2 ounce capacity. I had drained the oil before taking the motor to the dealer.
I corrected the oil level and went to start the motor. It would not start. About once in every about twenty pulls it would turn over, sputter a few seconds, and stall.
Can there be a connection between the starting problem and the motor being run with too much oil in the crankcase? Or do I need to look somewhere else for a solution?
Thanks for any help.
Joe

 

[ondarvr]

Yes, drain the carb and let some fuel flow though it, then try to start it.

 

[pvanv]

Overfilled oil, or laid on the wrong side can cause all sorts of issues. You want to check the level when the motor is vertical; Screw the dipstick in, pull it back out, and the oil level should be between the lines. Don't concern yourself with how many ounces go in, because there is always some residual oil in the pump, etc. Always verify on the stick. Too much oil could get into the intake and carb, or get into the cylinder. If you drain the carb as ondarvr mentioned, and pull out the plug, and then pull about 20 times (to clear any oil from the cylinder)... then check that plug (if oily, you can clean that off with carb spray), and reinstall the plug, refill the carb, and try again.

Also, if using the integral tank (most 5 hp models came with external tank setup), the tank needs to be relatively full to gravity-feed to the fuel pump to fill the carb.

 

[Joe Kay]

Thanks for the replies.
This morning I drained the carburetor and pumped some fuel through as you suggested. It started up on the second pull and ran strong. After a minute or so I pushed the choke back in and it stalled. I could not start it again. I then pulled the plug out and yanked the starter rope thirty times. The motor still would not start after I replaced the plug.
This evening I again drained the carb and filled the fuel tank with fresh 89 octane gas. It did not help.
Is it possible that the overfilling of the crankcase caused damage to the motor? The dealer who did the pre-delivery check told me that he ran the motor for one hour of the break-in period. Is it possible to run an engine that long with 23 ounces of oil in a crankcase with a 15 ounce capacity? I had drained the crankcase before transporting it to the dealer.
Any suggestions as to what I should try next?

 

[pvanv]

If it stalled without choke, it was too lean. The carb probably has some junk in it; it should be cleaned. It's under warranty, so if it's NOT a dirty carb, your dealer service is probably at no cost.

 

[Joe Kay]

I guess I'll have to take it to the dealer, although I don't have a lot of confidence in someone who overfilled the crankcase by so much. By the way, that motor was shipped to me with oil in the crankcase, filled to the full mark on the dipstick. It probably came that way from the manufacturer because the vendor is just that - a seller- This vendor does no repairs and sells no parts. I didn't mention that previously because the dealer who did the pre-delivery check found nothing wrong with the motor.

 

[pvanv]

The motors come to the US from Japan without oil in the crankcase (but with lube in the LU). Someone filled it.

 

[Joe Kay]

All I know is the crankcase had oil in when I received it and the vendor does not do repairs. He didn't do the pre-delivery check, so why would he put oil in?
Anyway, this morning I decided to check the spark plug. The gap was practically non-existent , less than .020 which is the narrowest my gauge can measure. The manual gives the correct gap as .031-.035. I don't know if it came that way from Japan or the dealer who did the pre-delivery check set the gap, but I did not. I replaced it with the spare plug that came with the motor. The gap was correct.
The motor started on the first pull and kept running. I ran it with the choke all the way out for about 5 minutes and then started to gradually push the choke in.
When the choke was half way in the motor began to stall but I was able to keep it running by using the throttle to make it idle faster. This way I was able to very gradually push the choke in and keep the motor from stalling. After about 15 minutes, the motor would not shut off with the throttle. I had to use the kill switch. I immediately tried to restart the motor. It would not start with choke in or out or halfway. That's when I went into the house and made myself a Manhattan - extra bourbon. A few hours later I went out and tried to start it, but no dice.
And this motor just came from an authorized Tohatsu dealer who was able to run the engine for one hour with a grossly overfilled crankcase and a greatly undergapped spark plug. I'm beginning to doubt that the dealer even ran the motor.

 

[fhhuber]

We used to gap plugs appx 0.010 to 0.15 for points based ignition (about 2X thickness of a matchbook cover, we actually used that to check the gap). 0.020 should run. (not correctly, but it is mainly a fuel economy issue)

Crankcase oil in the combustion chamber isn't good as it will rapidly put deposits on the head and piston. It also can fill the spark plug gap or coat the insulator and short out the plug. But you should see evidence of this on the plug.

Motor oil in the carb can make it not flow fuel properly, but gasoline will wash it out.

My dealer did not add the oil or do the break-in runs. They left that for me. New in box really meant new in a sealed box.

 

[pvanv]

All I know is the crankcase had oil in when I received it and the vendor does not do repairs. He didn't do the pre-delivery check, so why would he put oil in?
Anyway, this morning I decided to check the spark plug. The gap was practically non-existent , less than .020 which is the narrowest my gauge can measure. The manual gives the correct gap as .031-.035. I don't know if it came that way from Japan or the dealer who did the pre-delivery check set the gap, but I did not. I replaced it with the spare plug that came with the motor. The gap was correct.
The motor started on the first pull and kept running. I ran it with the choke all the way out for about 5 minutes and then started to gradually push the choke in.
When the choke was half way in the motor began to stall but I was able to keep it running by using the throttle to make it idle faster. This way I was able to very gradually push the choke in and keep the motor from stalling. After about 15 minutes, the motor would not shut off with the throttle. I had to use the kill switch. I immediately tried to restart the motor. It would not start with choke in or out or halfway. That's when I went into the house and made myself a Manhattan - extra bourbon. A few hours later I went out and tried to start it, but no dice.
And this motor just came from an authorized Tohatsu dealer who was able to run the engine for one hour with a grossly overfilled crankcase and a greatly undergapped spark plug. I'm beginning to doubt that the dealer even ran the motor.

I wonder whether you got a demo or used motor. Is the exact model MFS5C?

Correct gap is 0.035. Correct plug is NGK DCPR6E. Don't use "equivalent" plugs from other manufacturers. Sounds like someone dropped the plug, and it got slammed closed. Might then also have a crack in the insulator. That plug may be shot.

Unless it's below freezing, trying to run with the choke on for 5 minutes should result in a sputtering motor that eventually stalls, with a wet, black plug. In the summer temperatures in the US lower 48, maybe a few seconds to at most a half a minute, easing off as you go. Something is really wrong... probably way too lean from a crudded-up carb. If the motor was run, even just test-fired, and then allowed to sit for a week or 2 with fuel remaining in the carb bowl, the slow-speed passages are probably varnished (not covered by warranty), and will need a complete disassembly and thorough cleaning.

The motor is not supposed to shut off with the throttle; it's supposed to idle. You are supposed to press the kill switch to stop. I assume you got a manual with the motor, and already knew that, but were tired at that point.

Bourbon Manhattans are the best -- much better than rye, IMHO.

I think Tohatsu America might like to know which vendors don't do PDI or any service (were they mail order or online only?), and also which dealer gave you the motor with double the proper amount of oil in it after supposed PDI. What is your ZIP code?

 

[Joe Kay]

The business I bought the motor from is called Cumberland Water Sports and they do have physical stores in Tennesee and California. I met them at an outdoor show. The manual is for the MFS 4C, 5C and 6C and the box it came in was marked MFS 5C. I bought the motor last year but did not get to use it because I got it to use as a trolling motor for my Alumacraft boat with 90 hp Mercury and wasn't doing any trolling toward the end of the season. The motor was shipped from California. I'm assuming the vendor did not do the PDI because the checklist was not completed I did not even try to start the motor until after I had a dealer do the pre-delivery inspection earlier this year. He said there were no problems and that he ran the motor for one hour of the break-in procedure. He told me to do the rest of the break-in and bring the motor back. I asked for a copy of the checklist but he said he had to keep it on file in case it ever needs warranty work.

I am using the correct spark plug . It is the spare plug that came with the motor, same numbers correct gap.

I have owned quite a few motors over the years but this is my first 4 stroke. All my other small motors shut off when I throttled back. I have managed to start that motor only twice since I got it. The first time it ran fine until I pushed the choke in. It stalled and I could not re-start it. The second time was when I changed the plug. It started right up but if I pushed the choke in half way it would start to sputter.

You say a crudded up carburetor is not covered by the warranty. The motor was shipped to me with oil in the crankcase. I drained the oil before taking the motor for the PDI because I had to lay it down. It came back to me with an extra 8 ounces of oil in it. I'm thinking the factory ran the engine before shipping and the mechanic forgot to drain the oil. But if that caused the problem you would think that the dealer would have found a problem when he ran it. Something is wrong here.

I intend to notify Tohatsu and explain the problems.

You asked for my zipcode. It's 17954

Thanks for your input.

Joe

 

[pvanv]

Hmm. The perils of buying mail order. Cumberland sells a ton of motors, but the only ones they actually touch are the ones that they sell from the actual brick-and-mortar store, such as the Remote models, which must be dealer-installed. Frankly, they probably never saw the contents of the box... it could have been filled with concrete blocks, and they would never have known. It's highly unlikely that they did a PDI on your motor. They can and must do service, but they may not want to get involved in this case -- because of freight costs. It's always reasonable to call them and ask their recommendations. They owe it to you to see that you are satisfied.

The MFS4/5/6 is a very solid design -- almost indestructible. I never understood the popularity of the 5, since the 4, 5, and 6 are identical in every respect except for the carburetor and the stickers. They are all test run in Japan (but not for very long), and then the oil is drained for shipping overseas. I suppose it's possible that someone boxed it up without draining the crankcase, but I've never seen that, and I would have expected that the oil would have leaked all over during shipping... and that would be obvious.

If the carb was primed last fall, but not run, it is very likely that crud is in the carb. That, and the fact that it will only run with choke points to either a defective carburetor (extremely rare), or varnishing (or other junk) in the passages. The warranty is there to cover any manufacturing defects. The Factory can't control the consumer's actions or abuses, so varnishing is normally not covered by warranty. Any time the carb sits for a week or two with the dirty US fuels we get these days, varnishing is expected. That is why it's good practice to run the carb out at the end of each and every day... or, if that isn't possible, to drain the carb before storing for more than a couple of days. It's OK to lay the motor down (on the correct side) for transportation, so there is no need to drain the crankcase just to take the motor off the boat.

If your motor shuts off when throttled back, the idle is set too slow, or there is some other problem. They are all supposed to idle. On page 13 of your owners manual, you will see that the motor is supposed to idle at 1100 RPM in gear, 1300 in neutral.

I show 6 dealers within 50 miles of your ZIP code. You can find them by using the Dealer Locator feature of the Tohatsu website. You may want to call them and see what they can offer you for service, especially since it seems that the dealer you went to for the PDI wasn't very thorough. That said, I would at least contact that dealer and ask about the overfilling, wrong plug gap, etc.

Overfilling the 4/5/6 crankcase will cause running problems (including not starting, not idling, and limiting power), due to extreme crankcase pressures, but it typically does not cause permanent damage if only run briefly. Once you have the carburetion problem fixed, I would expect the motor to run very well.

Please post the resolution to the problem, so we can all know how it works out for you.