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  1. #1
    Petty Officer 1st Class texasvet54's Avatar
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    Default Engine turns over slow if at all

    Help. My 305cu.in Mercruiser won't spin fast enough to start. I suspect the starter, but I've not run into this situation with a starter before.

    I haven't started the engine in about two months as I've been cleaning the ethanol crap out of my fuel tank. So, between vacationing, grandkids, golf, and other stuff, I finally got it done. I bolted on the rebuilt carb, crossed my fingers and......... Jack Squat!!!!

    The starter went "clunk" and then barely spun the engine for a few seconds. Since the marine starting battery is 3 years old, I figured it was shot and bought an Excide battery at Academy. I installed it and had the same results. So, I took the new starting battery out of my bass boat and same thing. I even used my 200A starting option on my charger/starter that I brought from home and same-o, same-o.

    Before I started my gas tank project, the engine spun and started fine. Could it sitting for two months have caused a 14 year old starter to quit? After all, how many times has it really been called upon to work on a boat?

    Any ideas?

    Thanks,
    Texasvet

  2. #2
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Engine turns over slow if at all

    Could be nothing more than loose or corroded battery connections, or even cables that are about shot. Have seen too many with starting problems like you have only to find loose cable ends or cables that are only holding on by a few strands. (Each cable has two ends)

    Could also be a dragging starter. Wouldn't be the first one of those either.
    Don S.


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  3. #3
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Thanks Don. I'll crawl down there and check tomorrow.

    I'm also gonna pull the plugs and spin it to see if maybe I have a head gasket issue and maybe I got something in a cylinder or two. Whatcha think?

    Texasvet

  4. #4
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Don,

    I pulled the plugs and the engine spun just fine. One of the cylinders sprayed out quite a bit of gas. I had a remote starter, so I was able to quickly put my hand out and catch some of the spray. It was definitely gas.

    So, anyone have any thoughts?

    Also, As I posted a while back, it appears that fuel has been getting into my oil pan as the level on my dipstick keeps increasing and it is definitely not water. Does that rule out a cracked block?

    Texasvet

  5. #5
    Moderator Bondo's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by texasvet54 View Post
    Don,

    I pulled the plugs and the engine spun just fine. One of the cylinders sprayed out quite a bit of gas. I had a remote starter, so I was able to quickly put my hand out and catch some of the spray. It was definitely gas.

    So, anyone have any thoughts?

    Also, As I posted a while back, it appears that fuel has been getting into my oil pan as the level on my dipstick keeps increasing and it is definitely not water. Does that rule out a cracked block?

    Texasvet
    Ayuh,... What carb ya got,..?? Mechanical Fuel pump,..?? Could be Either, or Both...
    Any Grease is Better,..... Than No Grease at All.......

  6. #6
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Well, i just came from the marine shop and apparently the float pivot point sleave must not have been installed correctly when the carb was rebuilt so the carb was flooding and probably the problem.

    Tomorrow, I'll put everything back together and see what happens. I still have concerns about the problem with fuel in my oil, but one step at a time.

    Also, it's a 2 bbl Mercruiser rebuilt with an electric fuel pump.

    I haven't found a source for a new carb yet, so if anyone knows one I'd appreciate a link to it.

    Texasvet

  7. #7
    Lieutenant Junior Grade 81 Checkmate's Avatar
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    Default Re: Engine turns over slow if at all

    Just a guess...

    Someone put a Auto Mechanical fuel pump on and now the Diaphragm is blown causing your gas in the oil.

    Or check the little clear hose running from your fuel pump to the carb...Does it have gas in it? If it does...bad fuel pump. That would mean you have the correct marine fuel pump.

    Good Luck and let us know!
    1986 21' Celebrity BR - 350 Mercrusier I/O 260 H.P....Engine Serial #B427596
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    2001 24' Fisher Pontoon with 3.0 - 4 Cyclinder Mercrusier I/O...Eng Serial # OL647903
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  8. #8
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Checkmate,

    You must have been writing your reply as I was posting mine. It's an electric fuel pump that is bolted onto the front of the engine between the fuel/water separator and the carb. In some earlier posts I stated that the compression is good on every cylinder and the engine doesn't get hot whatsoever. The guy that I bought the houseboat from two years ago is an insurance salesman and realtor. If I called him now and asked for any history or if he knew that there was a problem with fuel getting into the oil when he sold me the boat, he'd cover his butt and plead ignorance.

    I'll put it all back together tomorrow and post the results.

    texasvet

  9. #9
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Good News......So Far.

    I cleaned the plugs up, put them back in, put the repaired carb back on, held my breath and cranked it.

    After a few seconds it started. I'm going to change the oil tomorrow since the fuel contaminated it and go from there.

    Texasvet.

  10. #10
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    The saga continues......

    So, as I stated a week ago, I pulled the plugs and the engine spun fine. Several days ago, I drained about 15 quarts of oil/fuel out of my crankcase that was a result of the carb float not being installed correctly during the rebuild. I even took the bolt out of the oil pan to get every last drop of crap out of the crankcase.

    Today, I went down and pulled the bolt out just to make sure that I got all of the crap out and about 8 ounces more drained out. I didn't spin the engine since the other day, so how in the wide world of sports did I get more fluid in my crankcase? I wasn't able to tell for sure what it was although it kinda smelled like more gas.

    If it was just an ounce, I'd say that it was just left over from the other day, but this was a considerable amount of fluid.

    Is there any way that I'm getting water back in through my exhaust while the engine is sitting? Remember, this is a houseboat with a 305 cu. in. Merc that sits in the water year round. Also, I have the electric fuel pump leads unplugged so it can't be that I'm somehow still pumping fuel.

    I'll take a look at the oil pan again tomorrow and if anything comes out when I pull the plug, I'll try to catch it.

    texasvet

  11. #11
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    Default Re: Engine turns over slow if at all

    sounds like the carb is not fixed yet.if you lift carb off see if you have pooling of fuel in the manifold or you may be able to see with a torch.

  12. #12
    Lieutenant Junior Grade spdracr39's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by dingdongs View Post
    sounds like the carb is not fixed yet.if you lift carb off see if you have pooling of fuel in the manifold or you may be able to see with a torch.
    Um in Texas is is called a flashlight DO NOT USE A TORCH
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  13. #13
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    I was just about to ask "how big a torch?" :-)

    I'm headed out to the boat a little later to see how the motor looks.

    Texasvet

  14. #14
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Well, I pulled the oil pan drain plug and only a few drops came out today. Tomorrow I'm going to cross my fingers and fill the engine with oil and spin it.

    texasvet

  15. #15
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    All,

    I pulled the oil pan plug last week and only a few drops of oil dripped out. So, I put 5 quarts of oil in and a new filter. I've now run the engine for 2 hours and it sounds great and the oil on the dipstick looks normal.

    Since I've had a lot of gas in my oil and crankcase, is there any treatment that I should perform on the engine to clean things up?

    thanks,
    texasvet

  16. #16
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by texasvet54 View Post
    All,

    I pulled the oil pan plug last week and only a few drops of oil dripped out. So, I put 5 quarts of oil in and a new filter. I've now run the engine for 2 hours and it sounds great and the oil on the dipstick looks normal.

    Since I've had a lot of gas in my oil and crankcase, is there any treatment that I should perform on the engine to clean things up?

    thanks,
    texasvet

    Complete tear down, inspection and rebuild would be the best treatment you could give that engine.

    Any engine that bound up from lack of oil can't be good or expected to last long.
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  17. #17
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by Don S View Post
    Complete tear down, inspection and rebuild would be the best treatment you could give that engine.

    Any engine that bound up from lack of oil can't be good or expected to last long.
    Hello Don,

    The engine wouldn't turn over because of the problem with the carb where the float was installed wrong thus allowing the cylinders to be filled with fuel. Fortunately, I didn't continue to try and turn it over, rather I pulled the plugs and spun it to clear all of the fuel. As I stated, the engine seems to be running fine, for now.

    As far as tearing it down, that's a no-go. I don't have anyone in the area that does major overhauls unless the boat is put on a trailer and hauled to their shop. Since the boat is 52' long and weighs 22,000 lbs, it would probably cost me 1K+ just to have it hauled out.


    Since I don't have a marina that can lift the boat out of the water, if I ever sell it, I'll replace it with a boat with dual outboards.
    texasvet

  18. #18
    Moderator Bondo's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by texasvet54 View Post
    All,

    I pulled the oil pan plug last week and only a few drops of oil dripped out. So, I put 5 quarts of oil in and a new filter. I've now run the engine for 2 hours and it sounds great and the oil on the dipstick looks normal.

    Since I've had a lot of gas in my oil and crankcase, is there any treatment that I should perform on the engine to clean things up?

    thanks,
    texasvet
    Ayuh,.... Clean it Up,..?? It's been gas-washed already,...

    If it has any chance at life, it's with good clean Oil...

    Do another change in 10, 20 hours, 'n Hope for the best...
    Any Grease is Better,..... Than No Grease at All.......

  19. #19
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by Bond-o View Post
    Ayuh,.... Clean it Up,..?? It's been gas-washed already,...

    If it has any chance at life, it's with good clean Oil...

    Do another change in 10, 20 hours, 'n Hope for the best...
    I figured that the gas gave the crankcase a cleaning that it normally doesn't get. My concern is whether or not the main and front seals need any special kind of treatment since they were washed in mostly fuel. My experience with additives that claim to recondition seals is that they are no more than snake oil.

    texasvet

  20. #20
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Crap. I ran the engine for a total of 3 hours and the level on my dipstick has come up about 1/4 inch and the dipstick smells like gas. I am so disgusted that I'm hoping for a fall tornado.

    To recap the condition of my engine:

    Compression good on all cylinders.

    Rebuilt carb (twice)

    Cleaned out 100 gal fuel tank.

    New plugs, wires, distr cap & rotor.

    Engine starts right up and runs smooth from idle to 3,000 rpm.

    I'm stuck on this one as is the local marine shop. To compound matters, I asked the marine shop if they could yank the heads or do whatever they thought needed to be done with the boat sitting in my slip and they said that I'd have to take the 250HP merc to them.

    Prayers or help would be appreciated.

    Texasvet

  21. #21
    Rear Admiral Maclin's Avatar
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    Default Re: Engine turns over slow if at all

    Yanking heads will not fix this. Fuel in the crankcase comes from the carb fuel bowl leaking into the intake manifold and around some open valves then seeping past the rings, or from a failed mechanical fuel pump dumping directly into the crankcase. You say you have an electric fuel pump so that leaves only the carb. It can be too full, maybe the needle/seat cannot seal against the pressure from the fuel pump and leak fuel in and it overflows into the carb bore after it has been run. A carb can also leak from the bottom, some models have plugs in the bottom of their carb bowls, those are just glued in and can leak after a while.

    Can you see any fuel seeping out from the butterfly plate shaft bushings?

  22. #22
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    Default Re: Engine turns over slow if at all

    is your fuel tank above the height of the engine as there seems to be a lot of fuel getting in the engine and its going up hill.is the pump still pumping after the engine is off?float may be set wrong and allowing excessive fuel to fill bowl and overflow down the throat of the carb.the only way is to find the fault as this is not correct.a manual is a mst for the relevant info for float setting and valve seating which lets the fuel in the carb.

  23. #23
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Thanks for the recent replies.

    The fuel tank is at the same level as the motor, but the pickup tube in the tank is probably 8 to 10 inches below where the hose attaches to the fuel/ water separator mounted on the engine.

    As far as the carb goes, when the marine shop re-positioned the float that was installed improperly during their rebuild, i saw that he didn't measure it's position.

    Texasvet

  24. #24
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    Default Re: Engine turns over slow if at all

    as the tank is fairly high the float will have to be reset and the valve on its seat has to be proved its working.if you strip it down it will not be hard to prove that it is sealing. its having a free syphon effect as the tank on most are in the bilge.an anti siphon valve will cure your symptoms but you'll have to look for the correct one .heres a sample; http://www.marinemechanic.com/asof-8-29/antsiphon.htm
    this style should fit on your fuel seperator as it has the same thread on the inlet side. http://www.moellermarine.com/afterma...ystems/valves/

  25. #25
    Petty Officer 1st Class texasvet54's Avatar
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    Default Re: Engine turns over slow if at all

    Quote Originally Posted by dingdongs View Post
    as the tank is fairly high the float will have to be reset and the valve on its seat has to be proved its working.if you strip it down it will not be hard to prove that it is sealing. its having a free syphon effect as the tank on most are in the bilge.an anti siphon valve will cure your symptoms but you'll have to look for the correct one .heres a sample; http://www.marinemechanic.com/asof-8-29/antsiphon.htm
    this style should fit on your fuel seperator as it has the same thread on the inlet side. http://www.moellermarine.com/afterma...ystems/valves/
    Well, a buddy of mine who's made a living as both an automotive mechanic and diesel mechanic took a look at my problem. We didn't pull the carb apart as we were short on time. He had me turn the engine off as he looked in the base of the carb and he didn't see any fuel pooling in the base. He suggested that as part of the troubleshooting, I should put an inline cutout valve prior to the fuel/water separator. If I read your post right, I think that is what you are suggesting with your anti-siphon valve. So, while none of us have said with certainty that it is the carb, we are looking at the fuel system as being the culprit, not the engine itself at this point.

    thanks,
    texasvet

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