bought a 1966 95hp, in storage 30 years,put in impeler kit,3 carb kits, 2 fuel pump kits, checked points, okay checked gap , good spark at all 6 plugs. motor starts and idles great. go for a ride and after about 10-15 minutes starts to sputer a bit then starts to boog down,no power and will die. let sit for 20-30 minutes and it fires right up and runs good again until it gets warmed up. good stream out the pee hole,does not apear to be getting hot. any ideas . Bryan P.S. still trying to get right pitch of a prop for boat, could this have anything to do with my problem?
motor boogs down
- Thread starter bluehorse
- Start date
Fun Times
Active Member
Hi, I was thinking you might want to try doing a compression test and a leak down test to the engine to check the head gasket and the valves to make sure they are still ok before you keep putting money in it for nothing. Here is some info in this link that covers a leak down test I happend to find while playing on the web if your in need of the info.http://www.aa1car.com/library/leakdown.htm I would do all the testing with the engine hot, Because that is when the engine seems to be running bad. Here is a link to find a leak down tester.http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=94190. http://www.harborfreight.com/cpi/ctaf/Category.taf?CategoryID=455.
Fun Times
Active Member
motor seems to run good from an idle to full throttle and then while crusing it will start to stumble a little and then gradually get worse until you are at full throttle and it is barely running. I did a compression test this morning and it was 135 on each hole except one and it was 140.I did notice some hard tan or brown deposits on the plugs which weren't there before. These are the plugs that were in it when I bought it, so they are 30 plus years old,but look okay. thanks Bryan Haven't done the other test yet as will have to make something up for that.
Fun Times
Active Member
If needed you could uses your compression testers hose for a leakdown. you connect the air compressure hose to the compression tester hose also make sure the schrader valve needel end is out of the hose. then pump air into a cylinder that is on the compression stroke [TDC]. Then lisen for air coming out the carb with it at [WOT] or out the exhaust system or the oil fill or the other spark plug holes 'ECT', And that might help you find out if something is bad and letting anything go by, But the only problem with that is you would not know how much is leaking passed with out a gauge. Did you do the compression test with a hot engine???
Hi bluehorse,
Sounds like a fun project - hopefully you'll show us some pics.
With those old motors, the ignition systems are pretty finicky.
It sounds like you've already done quite a bit of work. I would have a good look at the ignition system and overhaul it.
I gather it's a coil, condensor points set up?
Quite often the coils over time will become faulty, so they might run fine cold and then heat up and start to act up.
Some of those older motors can be a real challenge to get set-up properly, but once they are set up, they run really nice.
-Chris
Sounds like a fun project - hopefully you'll show us some pics.
With those old motors, the ignition systems are pretty finicky.
It sounds like you've already done quite a bit of work. I would have a good look at the ignition system and overhaul it.
I gather it's a coil, condensor points set up?
Quite often the coils over time will become faulty, so they might run fine cold and then heat up and start to act up.
Some of those older motors can be a real challenge to get set-up properly, but once they are set up, they run really nice.
-Chris
thanks alot chris I was thinking alot about the very same thing today. coils? local parts store has the old school 12 volt coils for about 45 bucks or from the merc dealer for about 75 bucks,thats each.I am still going to do the leak down test but hopefully it's only the coils, and I did do the compression test with the motor cold so I need to do it with the engine warm and see if there is a big difference from the cold test . any idea what the compression should be? thanks again Bryan (pics coming)
Bluehorse,
I've got a Seloc manual which I believe covers your year of motor.
What is the exact year and exact H.P.?
I don't list a 95 H.P. I've got a 90 listed.
Let me know and I'll see if there are specs for the compression. Generally, with compression, you want to see even figures. I little low is generally not the end of the world, but big differences from cylinder to cylinder are.
-Chris
I've got a Seloc manual which I believe covers your year of motor.
What is the exact year and exact H.P.?
I don't list a 95 H.P. I've got a 90 listed.
Let me know and I'll see if there are specs for the compression. Generally, with compression, you want to see even figures. I little low is generally not the end of the world, but big differences from cylinder to cylinder are.
-Chris
For '66, my manual lists a 80 HP and a 100 HP. For '64 or '65 they list a 90 HP.
I looked for the factory compression rates, but they weren't listed in the manual.
Which is kinda dumb....
-Chris
