engine kick back

[fat rat]

Could someone please tell me what cause's engine kick back......timming has been checked...doesn't do it all the time, when it does do it the starter won't even turn motor over.......thanx.

[sgdiv7]

I don't know what you mean by "kick back" but it sure sounds like a cylinder is full of water or fuel. That is the only thing that won't let the engine turn over that I know of, unless its possible that the rotors in the supercharger get out of time and bind up.Hope not, that could be expensive.
Bill

[spectras only]

Fat Rat ,the only time I experience a "kick back" by an engine ,when I forget to retard the timing on my 1947 Norton before I'm starting it.It could literally through me over the bike.Maybe the weights in your distributor stuck open,or as the previous post said you got water in your cylinders somehow [reversion?].

[fat rat]

I've checked every thing you guy's mentioned.....I thought the same thing, but its not. I went to a street rod show yesterday in hopes of talking with someone that has had this problem.....I saw a ton of blown rods there but it seems a lot of these guy's don't work on there own stuff....except one guy I met, who had a blown pro street vette and also has a blown fuel jet/drag boat......he says I have a meshing problem, which leads me back to the top mount starter that i have been having problems with......is there such a thing as a reverse rotation fly wheel??????

[nitro557]

hey man im at work now rex marine says when useing a top mount starter a reverse ring gear type flywheel should be used . they dont have a flywheel listing but looking at mercruiser listings they all use the same flywheel for lh and rh so beat me with a stick ill keep looking for a listing of a lh flywheel for ya

[nitro557]

i went out to the shop we have 2 engine jobs going on out there a sterndrive which is a bottom mount and a inboard which is a top mount the ring gears are alike and have no special directional cut like the starter drive does , im dam sorry but still no cure for your kick back , i think the bellhouseing alignment that we spoke about last night is it , call me and ill bring the crane and well do the swap

[spectras only]

Fat Rat,now that you mentioned it,when you use a top mount starter,you need a different flywheel[with BBC],or shimming the starter.Give Dave a call tuesday at California Marine 604-278 1880 .He'll tell you exactly what you need.

[BradP]

Call RB Performance in Parker. He specializes in starters. I had the same problem w/different starter he diagnosed problem on phone, provided starter and fixed my problem. Really knows his stuff. If you can't find his # e mail me and I'll look it up.

[BradP]

OOPS, Didn't finish my reply. Blower motors can "cough" when fired and jamb starter if not shimmed properly, I broke the snout off two stock starters before talking to RB.

[froggystyle]

Thea easy and proper fix for this is to run a starter button, and lock out your timing. I'm not going to get into what to lock it out at, as that seems to be THE heated debate question regarding blowers, but I do know that they love initial advance. Whatever your max advance is now, lock it there. Then, run a starter switch. Pump twice, turn the engine over using your new starter button with no ignition until it is fully spinning, then light off your ignition. Starts first time every time, and never kicks. Much easier on starters.
On a similar note, make sure you don't try to "keep it running" when starting it. Pumping your gas when starting will almost always cause a sneeze. Bad deal. Instead, just let it die, and do it again, but with half an extra pump. If the boat just will not idle, raise the idle. Also, the blower will run really cold-blooded until it heat-soaks, so keeping it running when cold can be a chore. In this case, I reach back and raise the idle to 1600 for the first five minutes, then turn it down to 1000 again.
Hope this helps.

[BLOWNDRAGBOAT]

I will make this quick....First of all if your engine is kicking than you have to much initial lead. A blower doesn't start adding significant cylinder preasure until its spinning at idle. Depending on the ignition your using, I ALWAYS install an MSD start retard box. It is a small module that removes your initial advance to say 10 degree's and allows the engine to turn over easier. Once the engine gets to 1300rpm, the MSD turns itself off and then you are on your timing curve as if nothing else were in place. It is MSD part #8982. This will elinate any engine kick. Also, since you have a top mounted starter, pull it back and hit the starter button to check it for proper operation. On blower motors I also like to use a hi torque starter with about a 3 or 4 to 1 ratio. They are pretty pricey but once you buy one its usually the last starter you ever have to buy. There are reverse rotation flex plates out there but unless your running this type of motor than I dought thats the problem. Besides, if its a jetboat than that means you aren't going anywhere. Unless you have a special pump, they are all standard rotation. You didn't indicate if this problem is new or if has been a problem since day one so I am guessing here. It doesnt matter if your using a top mount or side mount, they ALL use the same flexplate. If it's a BBC than it should be 168 tooth. If its a BBF, they have a tendency to start hard anyway. Only differance is location and shimming. Just to be on the safe side, pull the plugs and turn the motor over. If it turns over easily than that eliminates a couple of things. It will tell you that your blower rotors are not bound up, and it will tell you if you have water in a cylinder. It will also tell you just by sound that the starter and flexplate are at least meshing correctly. If (while the plugs are pulled) you still hear a loud noise in the bellhousing than you have a clearance problem. Check your mounting depth and while your at it, inspect the flexplate for broken or missing teeth. I fell like your problem is in your initial advance. Email me if you need to discuss it furthur. IT you want to call me at my shop feel free. BLOWNDRAGBOAT@YAHOO.COM

[froggystyle]

BDB just perfectly expressed plan "B". The MSD box is great, and does a better job of doing what I mentioned. BDB, do you need to run an MSD ignition to use it?
Either way, a stock mechanical advance is out.

[BLOWNDRAGBOAT]

Froggy......You can use it with just about any ignition manufacture. It has detailed instructions if you are using it with all other types. I use ALL MSD products with my engines so this is a plug-in item for me. Your SUPPOSE to use it with an MSD 6,7,8 or 10 series ingnition but I have installed a few on NON MSD systems and they work great. You can choose either 10Deg or 25Deg of retard. The timing willremain retarded until the module senses or reads 1300 rpm. After it reaches that rpm initially, Such as a quick stab of the throttle and it shuts itself off and bypasses to your initial advance curve. Its saves starters and flexplates as well as potential hazard to blower rotors.

[ponponracing]

Fatrat, what kind of a motor are you using? Racing(big boost) or pleasure(low boost). If your motor is a performance pleasure unit, the blower shouldn't give you enough pressure to cause kick back, even with high initial timing, since the static compression ratio should be between 7 and 8 to 1. If it is a racing unit, then it's a different story.

[Havasu Hangin']

Originally posted by BLOWNDRAGBOAT:
Your SUPPOSE to use it with an MSD 6,7,8 or 10 series ingnition...You can choose either 10Deg or 25Deg of retard. The timing willremain retarded until the module senses or reads 1300 rpm.
I installed one on my MSD marine box. I had to splice a wire or two (it didn't plug in like my rev limiter), but it works great. I wired mine to my cranking circut, so as soon as the cranking stops, the retard stops. I didn't use the second stage retard.
http://www.websitemonster.com/images/pimp.gif

[BLOWNDRAGBOAT]

I guess this is where gearheads disagree. I have seen it 5 or 6 times this year on some customers boats with the same kick problems. All but one of them was ignition related. After checking advance MOST not all, were WAY to far advanced. 2 of them were stock 502's (CARB VERSION) Someone put a pair of crate 502's in a Hallet against my recommendation and I ended up working on them several times for different owner induced problems. Good for me bad for him. Anyway, I have seen low compression motors kick although it is unusual. Without seeing it myself, I am guessing. You never stated what blower your running and at what boost, although during start up boost doesn't even come into play. When's the last time it ran good for you? Can you give me more detailed engine specs? Cubic inches,static compression ratio, ignition and timing. I can probably get closer to the problem with more info. Don't throw stuff at me PON. We can disagree and still be friends!!!!

[froggystyle]

What I have heard causes the kick back with advance is the blower cam profile. Usually large lobe centers with little overlap. Would this affect why it would kick back or not??? BTW Every blower motor I have seen at 38 deg total kicked back until a push button was installed ($20) or the MSD unit.

[fat rat]

I want to thank everyone for your inputs,the kick back happens once in 20 start ups, talked with Jay at Lighting yesterday and He's sending me a new motor mount and spacer.
I still have a meshing problem, that I need to fix first. I loosen the starter retorque it and it will roll over and start like it should 4-5 times, than it begins skipping and screaching and sometimes kicking back. I've checked all the teeth..nothing missing or worn.
The motor is a 7.8:1 running 5 lbs. boost, I checked the blower by rolling it over by hand it rolls over freely.

[fat rat]

If in fact I have to much intial timming would the kick back be an intermitting problem or everytime I go to start?
I pull the plugs after a kick back....it rolls over freely, the first time it happen i thought I was hydro-locked....expected water to come shooting out the spark plug holes, dry as a bone. I'll keep you posted with updates. I still welcome anyones advice and again thanx to all that have replied.

[froggystyle]

If you have a slug of water in a cylinder, It won't kick back, it will stop like you threw a wrench in the crank. Very dramatic.