more 245 ?'s and problems

[boilerdawg]

the "new to me 245" carbed merc still has some problems. i checked the reeds and sure nuff they werent sealing well, i could see daylight at the seals so i ordered and replaced em with the TDR reeds. that helped to some degree as now the mota dont die when you get outta it. however it does still backfire a good deal just before planing out. it will backfire at least 2 times sometimes 3 before the boat reaches plane. could this be a coil breaking down under heavy load? any ideas?

also i have another problem. this really has me puzzled. i checked full advanced timing. i went thru all the steps, found TDC, ccw to .150 and set the pointer on the 25*mark. im confident i did this right as the pointer was just slightly off the mark. i put the timing light on it and the mark wasnt any where near where it shoulda been. so i try to set the timing. i cannot get the 25*mark to line up. the trigger assembly physically will not go that far around. the round plastic knuckle that the linkage fits in on the trigger is hitting the column stand that the stator is mounted to. it gets to about 24* but not the 25*. i didnt leave the timing like this. i feel like something else is goin here so i put the timing back to where it was orginally before i messed with it. now im wondering whats wrong. is it the wrong trigger? i replaced the trigger when i bought the mota with one off a 260. the numbers would cross reference. is the flywheel magnets screwed up? any ideas, thoughts appreciated.

[j_martin]

If one of the trigger magnets were cracked, it would fire at the wrong time, or not at all. It would have to be a visible crack to make any difference. I'd have that flywheel off in a heartbeat, just to be sure.

Hope it helps
John

[boilerdawg]

hey thanks john for the response. ill be pullin the flywheel off tonite, hopefully. ill check back in to let yall know what i find.

[Propster]

Good call on inspecting the trigger, that could be it. If you are hitting the stop on the trigger, you are too far advanced. If you hit the stop, you are probably at 27-30 BTDC. (The marks on the flywheel are 25 BTDC and 2 ATDC. The 245 does not have TDC marked).

I made the mistake of thinking that the 2 ATDC mark was TDC and tried to set the advance to 25 BTDC on the flywheel. If it had not hit the stop, I would ended up setting it at 27 BTDC. Even then, it still didn't backfire.

I then timed every cylinder by marking 0 and 25 BTDC for every cylinder with the dial indicator. Once I had them all marked, I checked all cylinders with a timing light. (insert one plug and wire and ground all other coil wires. Turn fuel pump off). I had a variance of 3 degrees. For safety, I set it so the most advanced cylinder was at 25 BTDC. I am still trying to track down the reason for the variance.

Time every cylinder. That will tell you what is going on with your ignition. I think you have some wires routed incorrectly. Check the switch box to coil wiring and trigger wiring connections with the manual. I would also check the bias wire to make sure it has continutity and is not damaged.

Also, weak coils would not cause it to backfire. It would foul plugs and and/or fail to reach max rpm.

[j_martin]

I'd quick check the wiring first. It's easier, and most of the wires should be labeled.

Maybe Big-AL could put up a diagram here.

John

[captcarb]

If the donut shaped magnet around the hub of the flywheel slips, that can prevent reaching full advance.

3 degrees variance in timing is not good. If the difference is bank to bank, measure your switch box bias resistances. Even if they are equal, if it is bank to bank I would suspect either a bad switch box or mismatched switch boxes.

jim

[David - WI]

Didn't some of those motors have an "idle stabilizer" box that had to be unplugged before you could check or set the timing?

[boilerdawg]

I'd quick check the wiring first. It's easier, and most of the wires should be labeled.

Maybe Big-AL could put up a diagram here.

John


If the donut shaped magnet around the hub of the flywheel slips, that can prevent reaching full advance.

3 degrees variance in timing is not good. If the difference is bank to bank, measure your switch box bias resistances. Even if they are equal, if it is bank to bank I would suspect either a bad switch box or mismatched switch boxes.

jim

im pretty confident the wiring is good. also this mota doenst have an idle stablizer module, it may have at one time but it dont now.

im familar with checking the switchboxes and i will do this. only it'll hafta wait till my off day, friday. i dont think ill have enuff daylight when i get off to get that done before then. so as it stands now ill pull the flywheel off tonite and check. than ill go to the switchboxes and test them out. hopefully ill find the problem by doin one of these. thanks for all the info and help. ill fill yall in as to what i find.
thanks again

[Propster]

Neither of my 245's had idle stabilizers. You probably know this but, the idle stabilizers would be connected in-line to the bias circuit between the switch boxes. If the bias wire is only a few inches long and only connects to the switch boxes, then it does not have an idle stabilizer.

[captcarb]

My comment about the switch boxes was directed to propster, and I should have said so. He has the 3 degree problem.

jim

[Propster]

Thanks Jim, I forgot to check what cylinders were off, so I couldn't isolate it to the switch boxes. I figured I had mis-matched switch boxes, but they all checked out to be performance boxes (9600 ohm).

[TD]

I think you should try an OMC .:cool:

[j_martin]

Speed kills, Buy OMC, live forever.:D

[boilerdawg]

ok heres an update...i pulled the flywheel off and inspected it. nothing wrong with it. no loose magnets, no cracked magnets, nuffin that i can see. what now? is it a/the switchboxes? the switchboxes on here are a14's. i have some that are not a14's they come off a 200 2.5 merc. will they work on a high performance mota? what exactly is the difference in these switchboxes? if it aint the switchboxes thats causing my timing problem what do yall think it is? as always thanks for any useful advice.

[boilerdawg]

also i have another problem. this really has me puzzled. i checked full advanced timing. i went thru all the steps, found TDC, ccw to .150 and set the pointer on the 25*mark. im confident i did this right as the pointer was just slightly off the mark. i put the timing light on it and the mark wasnt any where near where it shoulda been. so i try to set the timing. i cannot get the 25*mark to line up. the trigger assembly physically will not go that far around. the round plastic knuckle that the linkage fits in on the trigger is hitting the column stand that the stator is mounted to. it gets to about 24* but not the 25*. i didnt leave the timing like this. i feel like something else is goin here so i put the timing back to where it was orginally before i messed with it. now im wondering whats wrong. is it the wrong trigger? i replaced the trigger when i bought the mota with one off a 260. the numbers would cross reference. is the flywheel magnets screwed up? any ideas, thoughts appreciated.


ok heres an update. i didnt get to spend as much time on the mota as i wanted...honey dos, all the bad weather and a death in the family put me behind. anyway i did spend some time on it yesterday. i thought initially that the plastic knuckle of the trigger was hitting the stator column. well after i pulled the flywheel off and got a better look that is not whats stoppin the trigger from goin around the needed amount to get the timing at 25*. what is happenin is that the bottom of the trigger is hitting the top of a bolt mounted under the trigger. i aint sure which bolt it is and what its for yet cause i didnt have time to look any farther, but i think its one of the top four bolts that maybe hold the stator mounting stand.?? anyway i dont understand why its hitting it. i also noticed that the wires for the trigger are dragging on the top of the block really bad. you know....right where the wires exit the trigger. it kinda looks like the trigger is sitting lower than it should. is this possible? i dont know how it could be. the trigger looks like it is sittin in there like it oughta.
i know im rambling. ill find out exactly whats going on when i get a little more time to trouble shoot. i didnt want to leave you guys and not update yall on what ive found out so far. and who knows maybe somebody else has run into this. thanks and ill keep ya posted when i find out more.

[captcarb]

Someone installed a bolt that is too long.

jim

[j_martin]

That's a main bearing end cap bolt!!! Critical to say the least. The top main bearing holder is also the mount for the stator.
You'd better check them all, make sure they're right, and torque them properly.

hope it helps

John

[boilerdawg]

thanks john for the info and the advice. im hoping to get time this weekend to pull the stator off and get a better look at whats goin on. it almost looks like the trigger is sittin too low and its saddle/yoke/whatyamacallit. i say this cause the wires off the trigger (i mean right out of the trigger) are really rubbin hard on the top of the block. i dont know how this could be but thats what it looks like. ill check more this weekend.

[j_martin]

Here's a picture of my top end plate, after I butchered it with a dremmel tool Mexican mill to clear a 40 amp stator. The black thing sitting on top of the aluminum plate is the trigger. It clears the top of the inside ring by just a few thousanth's of an inch, so that when the stator goes down on top of it, there is a few thousanths of an inch clearance vertically. T-rex sayz hez proud of me for that chop job cause I didn't pay nobody big bucks to do it, i did it all by myself.

[j_martin]

By the way, keeping these old stiff trigger harnesses loose enough to travel freely seems to be quite a chore. Lead dress is critical.

hope it helps
John