3 days to go till I pick up my boat with a rebuilt motor!My plan is to try to spend around 15 hours running it in over 3 - 4 days. The first 100 litres will be at 25/1 and the plan is to vary the rpms every 5 - 10 mins.I thought it might be a little like a car, that is the best way to run it in is continuos versus stop/start. In the past this has meant I would go for a 5-6 hour blast up the highway and with the boat I'm planning to do a few trips up and down Sydney's amazing Hawkesbury River.Any other suggestions / tips ?
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Re: Running in a 84 Mariner 75hp after a Rebuild
Idle it for quite awhile at first. Go out gently for a half hour. Then tromp it, get on plane, then back-off to 3/4 throttle and run it around there but varying it a bit now and then. After the first hour, try full throttle for a few short bursts. If it holds, you're probably good to go. Just avoid long periods of full throttle for the first tank or two. Babying it too much can do more harm to a 2-stroke than pushing it to it's limits.After the first run, check the sparkplugs. They should burn evenly.
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hello here is a paragraph from the manual without auto blend fuel oil ratio is 25-1 for the first 30 gallons(113.5 liters).operate motor at varied throttle settings not to exceed 1/2 throttle.2500-3500 rpm for the first 10 hours.after the first 10 gallons (37,8 liters) outboard can be run at any speed. however, avoid sustained full throttle operation until all 30 gallons of 25-1 have been consumed this is from page1-12 of manual #90-86134--4 covering 75 hp inlines from seriel # 4590512 and up.
Well, 3 days has passed and believe it or not, it still isn't ready !i rang yesterday to make sure all is AOK for pick up the following day and there's been a hitch.2 of the rings are oversize by 30 thou and he's hoping the proper rings will arrive in time to finish the motor today. I can't help feeling like this is a convenient excuse and he's had a few easy jobs come in. He's had the boat for 19 days now, one would think he'd be trying to do it as quickly as possible to make room in the workshop for the next customer's boat. He'd also have a happy customer ( me ) who would tell all and sundry how happy I was with the service. What I don't understand is the total lack of customer service. IF it was my business, I would inform my client as to the status of his repair, not wait for the customer to call. I would also ensure that the customer at all times felt that he was important and I valued his decision to use my services. I was in business fror myself for 20 years and never spent a dollar on advertising as my customers did it for me. I guess if your in a position / business where there isn't alot of competition, you can afford to have the attitude my mechanic has. Hopefully, I have misjudged him and He'll be calling this afternoon saying the motor is ready to go, but I'm not holding my breath.
Well I have cooled down a little since the last post! Still not finished for the weekend but I did a few chores around the house and my better half is very happy while I undertook a little diversion therapy. On top of that, the weekend produced 2 overcast days so I haven't missed any real quality time on the water. I'm, wondering if my mechanic read this as on Fri afternoon I had a call from him letting me know that he has a couple of hours left tofinish off the job and I should pick it up today. I was very happy I didn't have to call him this time and with a lil luck, I won't need to see him unless it's to watch him race or to do a little warranty work.
Do yourself a favor on the break-in. This sounds very unorthodox, but I'll swear to you that it works and you will see better results and power out of that new engine. Take it out for the first time, let it warm up completely and then firewall it. Seriously, open her up full bore and let her climb up to WOT- then shut down and coast. Return back to idle and do that again. The science here is how rings seat. Rings and cylinders will wear to match each other. When you "baby" an engine and don't run it hard, the rings don't get enough pressure against them to seat themselves fully. You will get 80% or 90% seating. When you run it hard and maximize the pressures in the cylinders, you get a much higher chance of achieving 100% seating. Take any engine apart that has been "babied" and look at the pistons. See the brown stains down the sides of the piston, past the rings and on down? That's blow by and it is caused by a poor ring/wall seal. That doesn't happen when you break them in hard and get 100% contact. Your power goes up, your fuel consumption goes down and the engine itself will last longer because you're not getting as much burnt fuel by-products in the crankcase. This isn't BS- it's been documented and researched. I have torn down probably a 1,000 engines over the years and hands down, the worst machines I found were those driven by "little old ladies" that never really opened up the throttle. Low mileage vehicles that needed engines because of severe oil useage or excessive blow-by, causing high crankcase pressures and seal/gasket failure. So take it out and run it hard- you'll find that it runs much better later in life. UFM82
UFM82, that's exactly what my mechanic said and I have taken him at his word.After taking it back twice for little gremlins to be sorted, the motor is running like a new one and I'm very happy with its performance so far. My mechanic took it out on Friday and did exactly what your describing, we were dancing over the top of some 12 - 24" waves at 40 miles/hour .This guy races F1 superboats ( 300+hp) and he sure knows how to read the water / swell.
Running in a 84 Mariner 75hp after a Rebuild
My plan is to try to spend around 15 hours running it in over 3 - 4 days. The first 100 litres will be at 25/1 and the plan is to vary the rpms every 5 - 10 mins.
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