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Starter Issues - 4.3 mercruiser

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kirkll

Regular Contributor
My starter bendix drive has a tough time engaging sometimes. Sometimes i get a loud clunk sound, and then the bendix just spins with out engaging. Sometimes it does it just once or twice and then she engages fine. This is has been slowly getting worse for awhile now.

a few questions for you gents , if you don't mind. First of all i'm dealing with a 19' 1990 Blue Water, 4.3 mercruiser , 2 barrel carb.

The previous owner didn't do me any favors by putting a "New Motor" in it prior to selling it to me last spring. Oh it ran great the first time i took her out, and i shelled out the cash......but i've been working on it off and on all summer right into fall getting this thing running decent and safe again. It didn't take me long to figure out this was not a marine engine he put in. No water fuel separator, highly illegal fuel pump, had the wrong carb on it, etc..etc... I slowly went through it and got the the water pump, gimble bearings and new bellows replaced, along with the lower shift cable why i was at it. My wife really likes this old boat, and it's in pretty decent shape. The hull is sound, and when she's running right it has plenty of power with the right prop. i got a lot of boat education this year, and put a lot of elbow grease and labors of love into it....(Besides pulling my hair out now and then...)

So now here we are with the bendix drive going out in the starter. Being a rookie at marine mechanics myself i have no idea if a marine grade starter was even put on this engine, and actually I doubt it with everything else i've had to do to convert this motor to a point the coast guard wouldn't hang me by the yard arm.

I have verified it is a 4.3 motor and had a marine mechanic tell me he thought it was a truck motor due to the amount of power it has, but i need to change out the soft plugs to brass or stainless when i winterize it . For a 3000# glass boat it has plenty of power with a 19 degree prop. But i have to figure out what type of starter to buy for this baby. I have no engine ID numbers that i can find.

What do you think guys, can ya help me out here? Kirk
 
Most are the staggered bolt pattern. A pronounced"clunk" is typical of a hydrolock condition. Pull the spark plugs before trying the new starter.
 
Bt Doctur said:
Most are the staggered bolt pattern. A pronounced"clunk" is typical of a hydrolock condition. Pull the spark plugs before trying the new starter.
Click to expand...

what causes a hydrolock condition and why would pulling the spark plugs have anything to do with the starter?

how does “most are the staggered bolt pattern” help me?

can I get an interpretation please... Kirk
 
Maybe the previous owner didn’t replace the exhaust when installing the “new” engine and it’s leaking water into the cyls. A loose starter caused by using the wrong starter bolts can also cause a clunk because the starter is shifting under torque. Left uncorrected that can break starter bolts causing a whole new problem. Pull the starter out and check if it’s marine (should have a sticker that says J1171 Marine) if so make sure you’re using the right bolts. The starter pictured is the smaller lighter PMGR starter and does not require the front brace used on the older big heavy direct drive starter. If it’s a direct drive starter then you need that front brace. It’s a GM part so you can still find them try Jegs or Summit racing. If it’s not a marine unit just get a marine PMGR starter they are lighter easier to install and draw less current.
 
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kirkll said:
My starter bendix drive has a tough time engaging sometimes. Sometimes i get a loud clunk sound, and then the bendix just spins with out engaging. Sometimes it does it just once or twice and then she engages fine. This is has been slowly getting worse for awhile now.
It is doubtful that you have an old Bendix Drive starter motor on a 1990 4.3L engine.
Bendix is a brand name as well as being the term used for the very early automobile and marine starter motors.
The Bendix Drive principle is still used in many Outboard engines and in many small equipment engines.

Today's Marine Engine starter motors use a solenoid/lever action to kick the pinion gear/sprag clutch unit out into the ring gear.
The pinion gear/sprag clutch may be manufactured by one of many companies, including the Bendix Company......, but we don't call these a Bendix starter motor.
Examples:

starter motor pinion drive types.jpg

starter motor w solenoid and lever action.jpg


I have verified it is a 4.3 motor and had a marine mechanic tell me he thought it was a truck motor due to the amount of power it has, but i need to change out the soft plugs to brass or stainless when i winterize it . For a 3000# glass boat it has plenty of power with a 19 degree prop. But i have to figure out what type of starter to buy for this baby. I have no engine ID numbers that i can find.
Merc typically used the 168 tooth ring gear flywheel.
If that is the case with your engine, it means you want the starter motor with the staggered bolt pattern, as per what Bt Doctur showed you in post # 4.

The starter motor with the straight across bolt pattern is for the 153 tooth ring gear flywheel.


I would look for a HTGR/PMGR (high torque gear reduction/permanent magnet gear reduction) starter motor for Marine use, like what Bt Doctur shows in post # 4.

These are gear reduction and will spin the crankshaft faster.
Example:

s-l640.jpg

Click to expand...
 
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If you are running in lake or river then you can dispense with changing out the core plugs. The reason for using brass in a marine engine is the possibility of galvanic corrosion in the joint between the cast iron block and the carbon steel of the core plug due to the salt water acceleration of the process (if the boat sits in the water all the time). If you are keeping it on a trailer and using it in fresh, then I wouldn't bother.
As for starter motors, I will simply echo the advice already given.
I believe that you do indeed have a truck motor as this is a common swap especially on cheaper boats that get passed around a lot. The only caution is that the camshaft is not the correct grind for marine use. There are certain conditions in which water can be sucked into the cylinders when using a truck cam in a boat engine. Be very careful coming off plane or in a following sea at low speed. These are times when you're most vulnerable. The only way that you'll know it is the engine will just stop. If you're lucky that will be the worst of it...you'll just pull all the spark plugs out, eject the water with the starter, allow it to dry and retry to start it. However, if you are at anything much above tickover, the usual result is bent connecting rods.
So, while you're at it, so to speak, perhaps a cam and lifters would be the next purchase.
 
Excellent advice. Marine cams are engineered for a specific torque band. Usually involving less/more gradual lift and duration, more lobe separation....say 112 or 114 degrees. Have to help guard against low vacuum circumstances....unless exhaust is routed above the water.
 
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kirkll said:
what causes a hydrolock condition and why would pulling the spark plugs have anything to do with the starter?

how does “most are the staggered bolt pattern” help me?

can I get an interpretation please... Kirk
Click to expand...

This is how staged helps you - chevy used only two types of starters for all its engines . If you need to replace look under there for a straight or staggered bolt pattern order accordingly. Make sure whoever supplies the starter supplies bolts, some of the newer permanent magnet started use slightly shorter bolts.
 
Had a 350 Chev bend a rod.....ran pretty good after that but a strange knock. Piston was ever so slightly tapping a counterweight on crank at bottom of its stroke.
 
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It's possible your starter is not deep enough into the flywheel.

Since the age of the motor is unknown it may use 3/8 coarse starter bolts. If so, the newer, metric design starter (which you probably have) uses 10 mm bolts, which larger in diameter.

If this is the case the starter can be way out of alignment, for those starter bolts align the starter.

Pull a starter bolt and compare it with a known 3/8 coarse thread bolt. If that's the case, and your starter is the new metric type (likely)--then that is your problem.


Jeff

PS: Get back to us with your findings and, if my guess is correct, I"ll show you how to fix it.
 
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Re: "Sometimes i get a loud clunk sound, and then the bendix just spins with out engaging."...

Alternatively to hydrolock, it could be that the shaft that the starter pinion ( i.e. that gear that engages the flywheel) is rusted, i.e. part of the "bendix" system. The bendix moves this pinion to engage the flywheel to start the engine... How does this get rusted???? A combination of events and design features... In at least one boat that I'm "familiar" with (not mine!!), the bilge is relatively shallow under the engine and the "auto" feature of the bilge pump ( industry standard seems to be 2") does not turn the pump on until the water level in the bilge is more than 2". When the wter in the bilge gets that high (at least in one boat I know) water gets into the bell housing and when the engine starts and runs before the bilge water is high enough to start the pump, the flywheel in immersed in bilge water and a running engine "flings" it up to the starter ( even if top mounted) and wets it and eventually the shaft that the starter pin slides on gets rusty and the pinion does not engage the flywheel, The klunk that you hear may be the starter torque breaking free a rusted pinion so it will spin, but the bendix solenoid is not strong enough to overcome the rust on the shaft so the pinion will slide... unless you try multiple times and hammer it free...

Solution(s)...

1) Manually operate the bilge pump switch and pump bilge dry before EVER trying to start the engine...
2) Replace the existing bilge pump with one that sense water level by trying to pump water every 2 mins or so... These pump the bilge water level down until the pump won't get any more... WARNING!!! 2 Caveats... as a MINIMUM... the bilge pump should be on a "dual purpose" battery which will tolerate the demands of this pump better than the normal START duty battery.. Even better, shore side power to recharge/float the battery.

FWIW.... I don't see how "spins without engaging" is consistent with a hydrolock situation... and IMHO, you will need a new starter sooner rather than later regardless.

Per Jeff's post... if not metric, a peek at the starter pinion to see if it rusty is a flag.
 
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The original thread here was started in December of 2020, and long since been resolved with a new starter. Looks like we have a German spam post on this thread to me, and the web site administrator should be alerted.

But I sure appreciate your sharing you experience with this stuff.

But I can’t imagine having a bell housing so close to the bottom of a boat. My bilge pump sets right under the oil pan in the bilge with several inches above it. I’d have to over 8” of water in the bilge before it even hit the oil pan, and I’d have water on deck before the motor would quit running. Kirk
 
LOL... never noticed the date... However.. the particular boat I saw this on is a 24 ft 1983 Privateer "Renegade" straight inboard with a top mounted starter.
 
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fastjeff said:
It's possible your starter is not deep enough into the flywheel.

Since the age of the motor is unknown it may use 3/8 coarse starter bolts. If so, the newer, metric design starter (which you probably have) uses 10 mm bolts, which larger in diameter.

If this is the case the starter can be way out of alignment, for those starter bolts align the starter.

Pull a starter bolt and compare it with a known 3/8 coarse thread bolt. If that's the case, and your starter is the new metric type (likely)--then that is your problem.


Jeff

PS: Get back to us with your findings and, if my guess is correct, I"ll show you how to fix it.
Click to expand...
I have the same issue on my 4.3 , I have pulled my plugs they are excellent my engine is 1988-1991 my starter had been replaced prior to me owning the boat with a sierra brand, the starter bolts wer broke off when I bought it I have removed them an did some searching on my year an bought mercury oem replacements so I have the wrong starter ? And will Wilson brand work from the parts store ?
 
Because I serviced boats professionally, I'll ask this- how often has the Bendix shaft and gear been lubricated? This was one of the most neglected spots on the engines I serviced and personally, I blame boat manufacturers for this because they make servicing engines incredibly difficult, in some cases.

People who design boats should be required to service them for a year before they're allowed to have any say in the designs. If they had to do this, they would make access to the lower parts of the engines, sides of the engines and they would allow space for hands & arms to reach in.

If the Bendix shaft is dry and rusty, replace the solenoid and lube it annually.
 
Amen, that is my pet peeve especially with modern boats. I modified my old boat just to make it easier to work on. Modern I/Os, I don't think I'd buy any of them, horrible for service.
 
Ogbign said:
I have the same issue on my 4.3 , I have pulled my plugs they are excellent my engine is 1988-1991 my starter had been replaced prior to me owning the boat with a sierra brand, the starter bolts wer broke off when I bought it I have removed them an did some searching on my year an bought mercury oem replacements so I have the wrong starter ? And will Wilson brand work from the parts store ?
Click to expand...
Did you start your own thread? If so can you post link. I’m curious to see what the problem was.
 
louc said:
Amen, that is my pet peeve especially with modern boats. I modified my old boat just to make it easier to work on. Modern I/Os, I don't think I'd buy any of them, horrible for service.
Click to expand...
Only designed for the least cost to manufacture and to barely last past warranty time.
 
louc said:
Amen, that is my pet peeve especially with modern boats. I modified my old boat just to make it easier to work on. Modern I/Os, I don't think I'd buy any of them, horrible for service.
Click to expand...

IMO, the 'engineers' who design boats should be required to service them for a year. Maybe, just maybe, that would get them to think about access to components that need to be replaced.

Nahhhh!
 
Agreed!
A relative of mine has a 2020 Chapparal SSI 21’ with the Mercruiser 4.5. While it’s easy to winterize & change the oil, anything more that that would be very difficult. A starter replacement would likely require pulling the engine…unacceptable!
I am adding a remote oil filter mount & extending the block drains on my old 4.3 to make things easier. If I get a newer boat it will HAVE to be a 4 stroke outboard!
 
My issue was the starter bendix and gear I replaced my starter with a Wilson from Oreilly’s in June, it’s been working fine every since
 
louc said:
Agreed!
A relative of mine has a 2020 Chapparal SSI 21’ with the Mercruiser 4.5. While it’s easy to winterize & change the oil, anything more that that would be very difficult. A starter replacement would likely require pulling the engine…unacceptable!
I am adding a remote oil filter mount & extending the block drains on my old 4.3 to make things easier. If I get a newer boat it will HAVE to be a 4 stroke outboard!
Click to expand...
I have thought that all engines should have the oil filter relocation kit for a long time, especially after having to change the oil and filter in a 19' Rinker- what an absolute PITA! The side panels next to the engine were very high and had no openings to make access easy, unlike Regal boats and many others. I have ape arms, but if I had dropped the filter and it had fallen into the bilge, it would have been a mess that I'd need to clean up and I still don't know how I could have grabbed the filter if it had oil on it. I was talking with a friend about working on boats and he said that most of the ones he serviced weren't too bad and when I mentioned the Rinker, he just said "ugh..."- it's hard to convey the sound.

I had to Summerize a Larson bowrider and they didn't leave enough space between the stringer and raw water pump inlet/outlet, so the hoses couldn't be slid on with the hose clamps, they had to be added after the hoses were on the pump. The problem was that there wasn't enough room to use both hands- shoulders were wider than the opening, it was very far down in the compartment and the boat didn't have access from a lower place, either. The guy who Winterized is came over and said "You got this one, eh? I lost my religion on this POS".
 
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