Frustrated! please help? w 112 spl

[66 joe]

Guys, please help me take steps to get my motor back to normal.
Ill try 2 make this as short as possible. 96 112 spl, rebuilt power head. Orig blew up # 1 piston (found stuck thermostat and no active alarm horn)
Rebuilt .020 over, new water pump, thermostats, checked carbs and fuel pump. !st time out to lake, failed to start. Faulty starter, replaced cables and starter. 2nd time (today) started and launched, but no power, failed to get up on plane. Im suspecting faulty coil, which had chuck taken out of it. Have replacement and wires. Im just wondering how to go about identifying problem. Because the motor will sound and run fine on the driveway,,,, but the big test is under load. Im going to inspect plugs, and compression check first, but what next? I have a timing light.
just a little frustrated after spending all day replacing thermostats and still have trouble,,, but at least temp is bout 145 both heads. sorry for long post,, Joe

 

[bang4dabuck]

Re: Frustrated! please help? w 112 spl

Novice opinion. This sounds like something that happened to me on my 1981 Merc 70HP. It turned out to need a carb rebuild. High speed jets were blocked and could only get up to about 7 knots. I'd also look at fuel pump diaphram and fuel filter. These things I wouldn't notice in my driveway but will see in performance when under pressure. The fuel filter you might notice and if your diaphram is broke you might see fuel coming out lower unit.

If it feels rough I'd start looking at timing and electrical issues. Again novice opinion.

 

[tashasdaddy]

Re: Frustrated! please help? w 112 spl

carb cleaning, with rebuild kits, set timing, then linc n sinc. should put you back on the water. all of these thing get out of sinc when you rebuild.

http://forums.iboats.com/showthread.php?t=299680

 

[66 joe]

Re: Frustrated! please help? w 112 spl

Thanks for replies! I was hoping I didnt have to go through all these procedures, cause the motor ran so good last year. But I know the answer to that one. 1st suspect im going to check is the coil an spark. Hopefully I can identify that on the driveway. Also, when I was on lake,,, I was pulling plug wires to see if it would change and identify a dead hole, but I read somewhere pulling plug wires to running motor could damag power pack?!?!?!?!? OH NO! hope thats not my case now

 

[tashasdaddy]

Re: Frustrated! please help? w 112 spl

i pull wires all the time, never blew a power pack.

 

[pochejp]

Re: Frustrated! please help? w 112 spl

Guys, please help me take steps to get my motor back to normal.
Ill try 2 make this as short as possible. 96 112 spl, rebuilt power head. Orig blew up # 1 piston (found stuck thermostat and no active alarm horn)
Rebuilt .020 over, new water pump, thermostats, checked carbs and fuel pump. !st time out to lake, failed to start. Faulty starter, replaced cables and starter. 2nd time (today) started and launched, but no power, failed to get up on plane. Im suspecting faulty coil, which had chuck taken out of it. Have replacement and wires. Im just wondering how to go about identifying problem. Because the motor will sound and run fine on the driveway,,,, but the big test is under load. Im going to inspect plugs, and compression check first, but what next? I have a timing light.
just a little frustrated after spending all day replacing thermostats and still have trouble,,, but at least temp is bout 145 both heads. sorry for long post,, Joe

Rebuild the carbs. I went through the same issues with my 90HP. Those bottom jets are probably clogged up.

 

[66 joe]

Re: Frustrated! please help? w 112 spl

ive gone this far,,, the mechanic that rebuilt my powerhead looked at fuel pump and carbs and claimed they were ok,,,,, Ill have to question him some more. Is it normal to just completely die out when you get to higher rpms?
Thats a symptom,, would just die, but would re-start no problem. thanks, joe

 

[emdsapmgr]

Re: Frustrated! please help? w 112 spl

When the engine is in gear and under load, an inductive timing light will show weak (or misfires) on a plug wire. You need to check to insure all 4 wires have hot spark. Any engine overhaul must include a complete rebuild on both carbs. Why chance a new powerhead to a carb that may have a jet which might have some debris in it that could starve a new piston of fuel and lube? If the engine dies at high rpms, but restarts-could have a weak fuel pump (won't supply enough fuel to run high rpm's.)

 

[66 joe]

Re: Frustrated! please help? w 112 spl

Ill do both this week or have someone else do em,, carbs and fuel pump.
Getting impatient, wanna get back on water and these experimental trips to lake are getting me frustrated. Its just difficult to detect trouble on muffs.
And doesnt linc and sinc require on the water testing?

 

[aclmvh]

Re: Frustrated! please help? w 112 spl

Before spending too much time and money, check your plugs and spark- get one of the gap-type spark checkers to determine the health of your coil packs. And make sure those cylinders are all getting gas/oil.

 

[countvlad]

Re: Frustrated! please help? w 112 spl

Ill do both this week or have someone else do em,, carbs and fuel pump.
Getting impatient, wanna get back on water and these experimental trips to lake are getting me frustrated. Its just difficult to detect trouble on muffs.
And doesnt linc and sinc require on the water testing?

yes, i know how you feel but: Better Safe Than Sorry...

lic and sink does not require water testing.. once you get everything done your carbs should be lined up...

yes it is difficult to troubleshot problems on the muffs but sometimes you can only detect problems in the water

and from what i gather you dont have a manual.. which is very important when working on motor..... Get ONE good luck

 

[66 joe]

Re: Frustrated! please help? w 112 spl

Yes I do have oem shop manual, and these last 6 mos, learning it like the back of my hand. Just balancing work and family and boat repairs is getting the best of me. Im in pretty good with the marine mechanic that rebuilt power head and talked to him,,, he was thinking fuel pump over the phone and advsd me to bring it it. I like that idea, I know fuel pump or carb issues will not be that much $$$. Ill replace shady looking coils and spark plug wires and check sparks with timing light. one thing i notice on the new coils,,, looks like they ground through bolt on power head, and wondering if contacts are clean on old coils. the power head was repainted and I installed coils. dont remember it they were cleaned, If thats how they work

 

[emdsapmgr]

Re: Frustrated! please help? w 112 spl

If you repaint the powerhead, you need to sand off the paint buildup on the flat tips of the coil support brackets so that the coils make good ground to the powerhead.